diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index fba828a..c5436d7 100644
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,70 @@
+2019-10-18  Wenson Hsieh  <wenson_hsieh@apple.com>
+
+        [Clipboard API] Refactor Pasteboard::read() to take an optional item index
+        https://bugs.webkit.org/show_bug.cgi?id=203161
+
+        Reviewed by Tim Horton.
+
+        Adds an optional `itemIndex` argument to Pasteboard::read(PasteboardPlainText&) and
+        Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy). See below for more details.
+
+        Tests:  CopyHTML.ItemTypesWhenCopyingWebContent
+                PasteWebArchive.WebArchiveTypeIdentifier
+
+        * editing/mac/EditorMac.mm:
+        (WebCore::Editor::dataSelectionForPasteboard):
+
+        Recognize "com.apple.webarchive" alongside "Apple Web Archive pasteboard type" when writing and reading from the
+        platform pasteboard on macOS. We add support for this here because the existing private type cannot be written
+        to an NSPasteboardItem, since it does not conform to a valid UTI format. Luckily, there already exists a UTI
+        that represents a web archive, so we can use it instead.
+
+        We need to write and read web archive data from NSPasteboardItem in order to support the case where there are
+        multiple items in the pasteboard that contain different web archive data.
+
+        * platform/Pasteboard.h:
+        * platform/StaticPasteboard.h:
+        * platform/gtk/PasteboardGtk.cpp:
+        (WebCore::Pasteboard::read):
+        * platform/ios/PasteboardIOS.mm:
+        (WebCore::Pasteboard::read):
+
+        Read the string from `itemIndex` if specified; otherwise, fall back to index 0. This could actually be fixed in
+        the future to scan all pasteboard items for a suitable string instead of falling back on the first item, but for
+        now, we maintain the existing behavior.
+
+        (WebCore::Pasteboard::readRespectingUTIFidelities):
+
+        If an `itemIndex` is specified, ignore all other item indices when looking for suitable content.
+
+        * platform/libwpe/PasteboardLibWPE.cpp:
+        (WebCore::Pasteboard::read):
+        * platform/mac/DragDataMac.mm:
+        (WebCore::DragData::containsCompatibleContent const):
+        * platform/mac/PasteboardMac.mm:
+        (WebCore::Pasteboard::write):
+        (WebCore::readStringAtPreferredItemIndex):
+        (WebCore::readBufferAtPreferredItemIndex):
+
+        Add helper methods to read strings and buffers from the pasteboard, at an optional `itemIndex` if specified.
+
+        (WebCore::Pasteboard::read):
+
+        Adopt the helper functions when reading plain text and web content, and respect the given `itemIndex`. To do
+        this, we need to read both legacy and modern types from the pasteboard, instead of just legacy types. This is
+        because NSPasteboardItem on macOS only accepts and provides data in the form of modern pasteboard types.
+
+        * platform/mac/PlatformPasteboardMac.mm:
+        (WebCore::safeTypeForDOMToReadAndWriteForPlatformType):
+        (WebCore::PlatformPasteboard::readBuffer const):
+        (WebCore::PlatformPasteboard::readString const):
+
+        Fix these methods to accept platform pasteboard types instead of MIME types, to match the behavior of existing
+        readBuffer and readString methods in PlatformPasteboardIOS.
+
+        * platform/win/PasteboardWin.cpp:
+        (WebCore::Pasteboard::read):
+
 2019-10-18  Devin Rousso  <drousso@apple.com>
 
         [ASAN] Fix WebGPU tests after r250258
diff --git a/Source/WebCore/editing/mac/EditorMac.mm b/Source/WebCore/editing/mac/EditorMac.mm
index c12350c2..80abbe2 100644
--- a/Source/WebCore/editing/mac/EditorMac.mm
+++ b/Source/WebCore/editing/mac/EditorMac.mm
@@ -185,7 +185,7 @@
     if (!canCopy())
         return nullptr;
 
-    if (pasteboardType == WebArchivePboardType)
+    if (pasteboardType == WebArchivePboardType || pasteboardType == String(kUTTypeWebArchive))
         return selectionInWebArchiveFormat();
 
     if (pasteboardType == String(legacyRTFDPasteboardType()))
diff --git a/Source/WebCore/platform/Pasteboard.h b/Source/WebCore/platform/Pasteboard.h
index d518a95..3141325 100644
--- a/Source/WebCore/platform/Pasteboard.h
+++ b/Source/WebCore/platform/Pasteboard.h
@@ -198,8 +198,8 @@
     virtual WEBCORE_EXPORT void clear();
     virtual WEBCORE_EXPORT void clear(const String& type);
 
-    virtual WEBCORE_EXPORT void read(PasteboardPlainText&);
-    virtual WEBCORE_EXPORT void read(PasteboardWebContentReader&, WebContentReadingPolicy = WebContentReadingPolicy::AnyType);
+    virtual WEBCORE_EXPORT void read(PasteboardPlainText&, Optional<size_t> itemIndex = WTF::nullopt);
+    virtual WEBCORE_EXPORT void read(PasteboardWebContentReader&, WebContentReadingPolicy = WebContentReadingPolicy::AnyType, Optional<size_t> itemIndex = WTF::nullopt);
     virtual WEBCORE_EXPORT void read(PasteboardFileReader&);
 
     virtual WEBCORE_EXPORT void write(const Color&);
@@ -282,7 +282,7 @@
 private:
 #if PLATFORM(IOS_FAMILY)
     bool respectsUTIFidelities() const;
-    void readRespectingUTIFidelities(PasteboardWebContentReader&, WebContentReadingPolicy);
+    void readRespectingUTIFidelities(PasteboardWebContentReader&, WebContentReadingPolicy, Optional<size_t>);
 
     enum class ReaderResult {
         ReadType,
diff --git a/Source/WebCore/platform/StaticPasteboard.h b/Source/WebCore/platform/StaticPasteboard.h
index c9bff6f..0e764ea 100644
--- a/Source/WebCore/platform/StaticPasteboard.h
+++ b/Source/WebCore/platform/StaticPasteboard.h
@@ -56,8 +56,8 @@
     void clear() final;
     void clear(const String& type) final;
 
-    void read(PasteboardPlainText&) final { }
-    void read(PasteboardWebContentReader&, WebContentReadingPolicy) final { }
+    void read(PasteboardPlainText&, Optional<size_t> = WTF::nullopt) final { }
+    void read(PasteboardWebContentReader&, WebContentReadingPolicy, Optional<size_t> = WTF::nullopt) final { }
 
     void write(const PasteboardURL&) final { }
     void write(const PasteboardImage&) final { }
diff --git a/Source/WebCore/platform/gtk/PasteboardGtk.cpp b/Source/WebCore/platform/gtk/PasteboardGtk.cpp
index 62a772b..ec97f13 100644
--- a/Source/WebCore/platform/gtk/PasteboardGtk.cpp
+++ b/Source/WebCore/platform/gtk/PasteboardGtk.cpp
@@ -28,6 +28,7 @@
 #include "PlatformStrategies.h"
 #include "SelectionData.h"
 #include <wtf/NeverDestroyed.h>
+#include <wtf/Optional.h>
 #include <wtf/URL.h>
 
 namespace WebCore {
@@ -231,13 +232,13 @@
 }
 #endif
 
-void Pasteboard::read(PasteboardPlainText& text)
+void Pasteboard::read(PasteboardPlainText& text, Optional<size_t>)
 {
     readFromClipboard();
     text.text = m_selectionData->text();
 }
 
-void Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy)
+void Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy, Optional<size_t>)
 {
 }
 
diff --git a/Source/WebCore/platform/ios/PasteboardIOS.mm b/Source/WebCore/platform/ios/PasteboardIOS.mm
index e1ce2f3..f6273f0 100644
--- a/Source/WebCore/platform/ios/PasteboardIOS.mm
+++ b/Source/WebCore/platform/ios/PasteboardIOS.mm
@@ -150,18 +150,20 @@
     return true;
 }
 
-void Pasteboard::read(PasteboardPlainText& text)
+void Pasteboard::read(PasteboardPlainText& text, Optional<size_t> itemIndex)
 {
+    auto itemIndexToQuery = itemIndex.valueOr(0);
+
     PasteboardStrategy& strategy = *platformStrategies()->pasteboardStrategy();
-    text.text = strategy.readStringFromPasteboard(0, kUTTypeURL, m_pasteboardName);
+    text.text = strategy.readStringFromPasteboard(itemIndexToQuery, kUTTypeURL, m_pasteboardName);
     if (!text.text.isEmpty()) {
         text.isURL = true;
         return;
     }
 
-    text.text = strategy.readStringFromPasteboard(0, kUTTypePlainText, m_pasteboardName);
+    text.text = strategy.readStringFromPasteboard(itemIndexToQuery, kUTTypePlainText, m_pasteboardName);
     if (text.text.isEmpty())
-        text.text = strategy.readStringFromPasteboard(0, kUTTypeText, m_pasteboardName);
+        text.text = strategy.readStringFromPasteboard(itemIndexToQuery, kUTTypeText, m_pasteboardName);
 
     text.isURL = false;
 }
@@ -276,17 +278,17 @@
     return info.canBeTreatedAsAttachmentOrFile() || UTTypeConformsTo(contentTypeForHighestFidelityItem.createCFString().get(), kUTTypeVCard);
 }
 
-void Pasteboard::read(PasteboardWebContentReader& reader, WebContentReadingPolicy policy)
+void Pasteboard::read(PasteboardWebContentReader& reader, WebContentReadingPolicy policy, Optional<size_t> itemIndex)
 {
     reader.contentOrigin = readOrigin();
     if (respectsUTIFidelities()) {
-        readRespectingUTIFidelities(reader, policy);
+        readRespectingUTIFidelities(reader, policy, itemIndex);
         return;
     }
 
     PasteboardStrategy& strategy = *platformStrategies()->pasteboardStrategy();
 
-    int numberOfItems = strategy.getPasteboardItemsCount(m_pasteboardName);
+    size_t numberOfItems = strategy.getPasteboardItemsCount(m_pasteboardName);
 
     if (!numberOfItems)
         return;
@@ -300,7 +302,10 @@
     bool canReadAttachment = false;
 #endif
 
-    for (int i = 0; i < numberOfItems; i++) {
+    for (size_t i = 0; i < numberOfItems; i++) {
+        if (itemIndex && i != *itemIndex)
+            continue;
+
         auto info = strategy.informationForItemAtIndex(i, m_pasteboardName);
 #if ENABLE(ATTACHMENT_ELEMENT)
         if (canReadAttachment && prefersAttachmentRepresentation(info)) {
@@ -336,11 +341,14 @@
     return m_pasteboardName == "data interaction pasteboard";
 }
 
-void Pasteboard::readRespectingUTIFidelities(PasteboardWebContentReader& reader, WebContentReadingPolicy policy)
+void Pasteboard::readRespectingUTIFidelities(PasteboardWebContentReader& reader, WebContentReadingPolicy policy, Optional<size_t> itemIndex)
 {
     ASSERT(respectsUTIFidelities());
     auto& strategy = *platformStrategies()->pasteboardStrategy();
     for (NSUInteger index = 0, numberOfItems = strategy.getPasteboardItemsCount(m_pasteboardName); index < numberOfItems; ++index) {
+        if (itemIndex && index != *itemIndex)
+            continue;
+
 #if ENABLE(ATTACHMENT_ELEMENT)
         auto info = strategy.informationForItemAtIndex(index, m_pasteboardName);
         auto attachmentFilePath = info.pathForHighestFidelityItem();
diff --git a/Source/WebCore/platform/libwpe/PasteboardLibWPE.cpp b/Source/WebCore/platform/libwpe/PasteboardLibWPE.cpp
index 368f937..7d78009 100644
--- a/Source/WebCore/platform/libwpe/PasteboardLibWPE.cpp
+++ b/Source/WebCore/platform/libwpe/PasteboardLibWPE.cpp
@@ -31,6 +31,7 @@
 #include "NotImplemented.h"
 #include "PasteboardStrategy.h"
 #include "PlatformStrategies.h"
+#include <wtf/Optional.h>
 
 namespace WebCore {
 
@@ -94,12 +95,12 @@
 {
 }
 
-void Pasteboard::read(PasteboardPlainText& text)
+void Pasteboard::read(PasteboardPlainText& text, Optional<size_t>)
 {
     text.text = platformStrategies()->pasteboardStrategy()->readStringFromPasteboard(0, "text/plain;charset=utf-8", name());
 }
 
-void Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy)
+void Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy, Optional<size_t>)
 {
     notImplemented();
 }
diff --git a/Source/WebCore/platform/mac/DragDataMac.mm b/Source/WebCore/platform/mac/DragDataMac.mm
index 64e4894..aa3b03b 100644
--- a/Source/WebCore/platform/mac/DragDataMac.mm
+++ b/Source/WebCore/platform/mac/DragDataMac.mm
@@ -237,6 +237,7 @@
     platformStrategies()->pasteboardStrategy()->getTypes(types, m_pasteboardName);
     return types.contains(String(WebArchivePboardType))
         || types.contains(htmlPasteboardType())
+        || types.contains(String(kUTTypeWebArchive))
 #if PLATFORM(MAC)
         || types.contains(String(legacyFilenamesPasteboardType()))
         || types.contains(String(legacyFilesPromisePasteboardType()))
diff --git a/Source/WebCore/platform/mac/PasteboardMac.mm b/Source/WebCore/platform/mac/PasteboardMac.mm
index c1ecef1..a3e4b29 100644
--- a/Source/WebCore/platform/mac/PasteboardMac.mm
+++ b/Source/WebCore/platform/mac/PasteboardMac.mm
@@ -129,8 +129,10 @@
 
     if (content.canSmartCopyOrDelete)
         types.append(WebSmartPastePboardType);
-    if (content.dataInWebArchiveFormat)
+    if (content.dataInWebArchiveFormat) {
         types.append(WebArchivePboardType);
+        types.append(kUTTypeWebArchive);
+    }
     if (content.dataInRTFDFormat)
         types.append(String(legacyRTFDPasteboardType()));
     if (content.dataInRTFFormat)
@@ -144,13 +146,18 @@
 
     m_changeCount = platformStrategies()->pasteboardStrategy()->setTypes(types, m_pasteboardName);
 
+    // FIXME: The following code should be refactored, such that it only requires a single call out to the client layer.
+    // In WebKit2, this currently results in many unnecessary synchronous round-trip IPC messages.
+
     ASSERT(content.clientTypes.size() == content.clientData.size());
     for (size_t i = 0, size = content.clientTypes.size(); i < size; ++i)
         m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(content.clientData[i].get(), content.clientTypes[i], m_pasteboardName);
     if (content.canSmartCopyOrDelete)
         m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(nullptr, WebSmartPastePboardType, m_pasteboardName);
-    if (content.dataInWebArchiveFormat)
+    if (content.dataInWebArchiveFormat) {
         m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(content.dataInWebArchiveFormat.get(), WebArchivePboardType, m_pasteboardName);
+        m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(content.dataInWebArchiveFormat.get(), kUTTypeWebArchive, m_pasteboardName);
+    }
     if (content.dataInRTFDFormat)
         m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(content.dataInRTFDFormat.get(), legacyRTFDPasteboardType(), m_pasteboardName);
     if (content.dataInRTFFormat)
@@ -258,13 +265,17 @@
     ASSERT(MIMETypeRegistry::isSupportedImageMIMEType(pasteboardImage.resourceMIMEType));
 
     auto types = writableTypesForImage();
-    if (pasteboardImage.dataInWebArchiveFormat)
+    if (pasteboardImage.dataInWebArchiveFormat) {
         types.append(WebArchivePboardType);
+        types.append(kUTTypeWebArchive);
+    }
 
     m_changeCount = writeURLForTypes(types, m_pasteboardName, pasteboardImage.url);
     m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(SharedBuffer::create(imageData).ptr(), legacyTIFFPasteboardType(), m_pasteboardName);
-    if (pasteboardImage.dataInWebArchiveFormat)
-        m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(pasteboardImage.dataInWebArchiveFormat.get(), WebArchivePboardType, m_pasteboardName);
+    if (auto archiveData = pasteboardImage.dataInWebArchiveFormat) {
+        m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(archiveData.get(), WebArchivePboardType, m_pasteboardName);
+        m_changeCount = platformStrategies()->pasteboardStrategy()->setBufferForType(archiveData.get(), kUTTypeWebArchive, m_pasteboardName);
+    }
     writeFileWrapperAsRTFDAttachment(fileWrapper(pasteboardImage), m_pasteboardName, m_changeCount);
 }
 
@@ -293,28 +304,55 @@
     return builder.toString();
 }
 
-void Pasteboard::read(PasteboardPlainText& text)
+static String readStringAtPreferredItemIndex(const String& type, Optional<size_t> itemIndex, PasteboardStrategy& strategy, const String& pasteboardName)
 {
-    PasteboardStrategy& strategy = *platformStrategies()->pasteboardStrategy();
+    if (itemIndex)
+        return strategy.readStringFromPasteboard(*itemIndex, type, pasteboardName);
+    return strategy.stringForType(type, pasteboardName);
+}
+
+static RefPtr<SharedBuffer> readBufferAtPreferredItemIndex(const String& type, Optional<size_t> itemIndex, PasteboardStrategy& strategy, const String& pasteboardName)
+{
+    if (itemIndex)
+        return strategy.readBufferFromPasteboard(*itemIndex, type, pasteboardName);
+    return strategy.bufferForType(type, pasteboardName);
+}
+
+void Pasteboard::read(PasteboardPlainText& text, Optional<size_t> itemIndex)
+{
+    auto& strategy = *platformStrategies()->pasteboardStrategy();
 
     Vector<String> types;
-    strategy.getTypes(types, m_pasteboardName);
+    if (itemIndex)
+        types = strategy.informationForItemAtIndex(*itemIndex , m_pasteboardName).platformTypesByFidelity;
+    else
+        strategy.getTypes(types, m_pasteboardName);
 
     if (types.contains(String(NSPasteboardTypeString))) {
-        text.text = strategy.stringForType(NSPasteboardTypeString, m_pasteboardName);
+        text.text = readStringAtPreferredItemIndex(NSPasteboardTypeString, itemIndex, strategy, m_pasteboardName);
         text.isURL = false;
         return;
     }
 
     if (types.contains(String(legacyStringPasteboardType()))) {
-        text.text = strategy.stringForType(legacyStringPasteboardType(), m_pasteboardName);
+        text.text = readStringAtPreferredItemIndex(legacyStringPasteboardType(), itemIndex, strategy, m_pasteboardName);
         text.isURL = false;
         return;
     }
     
     if (types.contains(String(legacyRTFDPasteboardType()))) {
-        if (RefPtr<SharedBuffer> data = strategy.bufferForType(legacyRTFDPasteboardType(), m_pasteboardName)) {
-            if (auto attributedString = adoptNS([[NSAttributedString alloc] initWithRTFD:data->createNSData().get() documentAttributes:NULL])) {
+        if (auto data = readBufferAtPreferredItemIndex(legacyRTFDPasteboardType(), itemIndex, strategy, m_pasteboardName)) {
+            if (auto attributedString = adoptNS([[NSAttributedString alloc] initWithRTFD:data->createNSData().get() documentAttributes:nil])) {
+                text.text = [attributedString string];
+                text.isURL = false;
+                return;
+            }
+        }
+    }
+
+    if (types.contains(String(NSPasteboardTypeRTFD))) {
+        if (auto data = readBufferAtPreferredItemIndex(NSPasteboardTypeRTFD, itemIndex, strategy, m_pasteboardName)) {
+            if (auto attributedString = adoptNS([[NSAttributedString alloc] initWithRTFD:data->createNSData().get() documentAttributes:nil])) {
                 text.text = [attributedString string];
                 text.isURL = false;
                 return;
@@ -323,8 +361,18 @@
     }
 
     if (types.contains(String(legacyRTFPasteboardType()))) {
-        if (RefPtr<SharedBuffer> data = strategy.bufferForType(legacyRTFPasteboardType(), m_pasteboardName)) {
-            if (auto attributedString = adoptNS([[NSAttributedString alloc] initWithRTF:data->createNSData().get() documentAttributes:NULL])) {
+        if (auto data = readBufferAtPreferredItemIndex(legacyRTFPasteboardType(), itemIndex, strategy, m_pasteboardName)) {
+            if (auto attributedString = adoptNS([[NSAttributedString alloc] initWithRTF:data->createNSData().get() documentAttributes:nil])) {
+                text.text = [attributedString string];
+                text.isURL = false;
+                return;
+            }
+        }
+    }
+
+    if (types.contains(String(NSPasteboardTypeRTF))) {
+        if (auto data = readBufferAtPreferredItemIndex(NSPasteboardTypeRTF, itemIndex, strategy, m_pasteboardName)) {
+            if (auto attributedString = adoptNS([[NSAttributedString alloc] initWithRTF:data->createNSData().get() documentAttributes:nil])) {
                 text.text = [attributedString string];
                 text.isURL = false;
                 return;
@@ -347,21 +395,31 @@
     }
 
     // FIXME: The code above looks at the types vector first, but this just gets the string without checking. Why the difference?
-    text.text = strategy.stringForType(legacyURLPasteboardType(), m_pasteboardName);
+    text.text = readStringAtPreferredItemIndex(legacyURLPasteboardType(), itemIndex, strategy, m_pasteboardName);
     text.isURL = !text.text.isNull();
 }
 
-void Pasteboard::read(PasteboardWebContentReader& reader, WebContentReadingPolicy policy)
+void Pasteboard::read(PasteboardWebContentReader& reader, WebContentReadingPolicy policy, Optional<size_t> itemIndex)
 {
-    PasteboardStrategy& strategy = *platformStrategies()->pasteboardStrategy();
+    auto& strategy = *platformStrategies()->pasteboardStrategy();
 
     Vector<String> types;
-    strategy.getTypes(types, m_pasteboardName);
+    if (itemIndex)
+        types = strategy.informationForItemAtIndex(*itemIndex , m_pasteboardName).platformTypesByFidelity;
+    else
+        strategy.getTypes(types, m_pasteboardName);
 
     reader.contentOrigin = readOrigin();
 
     if (types.contains(WebArchivePboardType)) {
-        if (auto buffer = strategy.bufferForType(WebArchivePboardType, m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(WebArchivePboardType, itemIndex, strategy, m_pasteboardName)) {
+            if (m_changeCount != changeCount() || reader.readWebArchive(*buffer))
+                return;
+        }
+    }
+
+    if (types.contains(String(kUTTypeWebArchive))) {
+        if (auto buffer = readBufferAtPreferredItemIndex(kUTTypeWebArchive, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readWebArchive(*buffer))
                 return;
         }
@@ -380,20 +438,40 @@
     }
 
     if (types.contains(String(legacyHTMLPasteboardType()))) {
-        String string = strategy.stringForType(legacyHTMLPasteboardType(), m_pasteboardName);
+        String string = readStringAtPreferredItemIndex(legacyHTMLPasteboardType(), itemIndex, strategy, m_pasteboardName);
+        if (m_changeCount != changeCount() || (!string.isNull() && reader.readHTML(string)))
+            return;
+    }
+
+    if (types.contains(String(NSPasteboardTypeHTML))) {
+        String string = readStringAtPreferredItemIndex(NSPasteboardTypeHTML, itemIndex, strategy, m_pasteboardName);
         if (m_changeCount != changeCount() || (!string.isNull() && reader.readHTML(string)))
             return;
     }
 
     if (types.contains(String(legacyRTFDPasteboardType()))) {
-        if (RefPtr<SharedBuffer> buffer = strategy.bufferForType(legacyRTFDPasteboardType(), m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(legacyRTFDPasteboardType(), itemIndex, strategy, m_pasteboardName)) {
+            if (m_changeCount != changeCount() || reader.readRTFD(*buffer))
+                return;
+        }
+    }
+
+    if (types.contains(String(NSPasteboardTypeRTFD))) {
+        if (auto buffer = readBufferAtPreferredItemIndex(NSPasteboardTypeRTFD, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readRTFD(*buffer))
                 return;
         }
     }
 
     if (types.contains(String(legacyRTFPasteboardType()))) {
-        if (RefPtr<SharedBuffer> buffer = strategy.bufferForType(legacyRTFPasteboardType(), m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(legacyRTFPasteboardType(), itemIndex, strategy, m_pasteboardName)) {
+            if (m_changeCount != changeCount() || reader.readRTF(*buffer))
+                return;
+        }
+    }
+
+    if (types.contains(String(NSPasteboardTypeRTF))) {
+        if (auto buffer = readBufferAtPreferredItemIndex(NSPasteboardTypeRTF, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readRTF(*buffer))
                 return;
         }
@@ -403,28 +481,42 @@
         return;
 
     if (types.contains(String(legacyTIFFPasteboardType()))) {
-        if (RefPtr<SharedBuffer> buffer = strategy.bufferForType(legacyTIFFPasteboardType(), m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(legacyTIFFPasteboardType(), itemIndex, strategy, m_pasteboardName)) {
+            if (m_changeCount != changeCount() || reader.readImage(buffer.releaseNonNull(), "image/tiff"_s))
+                return;
+        }
+    }
+
+    if (types.contains(String(NSPasteboardTypeTIFF))) {
+        if (auto buffer = readBufferAtPreferredItemIndex(NSPasteboardTypeTIFF, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readImage(buffer.releaseNonNull(), "image/tiff"_s))
                 return;
         }
     }
 
     if (types.contains(String(legacyPDFPasteboardType()))) {
-        if (RefPtr<SharedBuffer> buffer = strategy.bufferForType(legacyPDFPasteboardType(), m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(legacyPDFPasteboardType(), itemIndex, strategy, m_pasteboardName)) {
+            if (m_changeCount != changeCount() || reader.readImage(buffer.releaseNonNull(), "application/pdf"_s))
+                return;
+        }
+    }
+
+    if (types.contains(String(NSPasteboardTypePDF))) {
+        if (auto buffer = readBufferAtPreferredItemIndex(NSPasteboardTypePDF, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readImage(buffer.releaseNonNull(), "application/pdf"_s))
                 return;
         }
     }
 
     if (types.contains(String(kUTTypePNG))) {
-        if (RefPtr<SharedBuffer> buffer = strategy.bufferForType(kUTTypePNG, m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(kUTTypePNG, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readImage(buffer.releaseNonNull(), "image/png"_s))
                 return;
         }
     }
 
     if (types.contains(String(kUTTypeJPEG))) {
-        if (RefPtr<SharedBuffer> buffer = strategy.bufferForType(kUTTypeJPEG, m_pasteboardName)) {
+        if (auto buffer = readBufferAtPreferredItemIndex(kUTTypeJPEG, itemIndex, strategy, m_pasteboardName)) {
             if (m_changeCount != changeCount() || reader.readImage(buffer.releaseNonNull(), "image/jpeg"_s))
                 return;
         }
@@ -432,13 +524,13 @@
 
     if (types.contains(String(legacyURLPasteboardType()))) {
         URL url = strategy.url(m_pasteboardName);
-        String title = strategy.stringForType(WebURLNamePboardType, m_pasteboardName);
+        String title = readStringAtPreferredItemIndex(WebURLNamePboardType, itemIndex, strategy, m_pasteboardName);
         if (m_changeCount != changeCount() || (!url.isNull() && reader.readURL(url, title)))
             return;
     }
 
     if (types.contains(String(legacyStringPasteboardType()))) {
-        String string = strategy.stringForType(legacyStringPasteboardType(), m_pasteboardName);
+        String string = readStringAtPreferredItemIndex(legacyStringPasteboardType(), itemIndex, strategy, m_pasteboardName);
         if (m_changeCount != changeCount() || (!string.isNull() && reader.readPlainText(string)))
             return;
     }
diff --git a/Source/WebCore/platform/mac/PlatformPasteboardMac.mm b/Source/WebCore/platform/mac/PlatformPasteboardMac.mm
index 718126a..f5e4c40 100644
--- a/Source/WebCore/platform/mac/PlatformPasteboardMac.mm
+++ b/Source/WebCore/platform/mac/PlatformPasteboardMac.mm
@@ -186,7 +186,7 @@
     if (platformType == String(legacyURLPasteboardType()))
         return "text/uri-list"_s;
 
-    if (platformType == String(legacyHTMLPasteboardType()) || platformType == String(WebArchivePboardType)
+    if (platformType == String(legacyHTMLPasteboardType()) || platformType == String(WebArchivePboardType) || platformType == String(kUTTypeWebArchive)
         || platformType == String(legacyRTFDPasteboardType()) || platformType == String(legacyRTFPasteboardType()))
         return "text/html"_s;
 
@@ -420,11 +420,7 @@
     if (!item)
         return { };
 
-    auto platformType = modernPasteboardTypeForWebSafeMIMEType(type);
-    if (!platformType)
-        return nullptr;
-
-    if (NSData *data = [item dataForType:platformType]) {
+    if (NSData *data = [item dataForType:type]) {
         auto nsData = adoptNS(data.copy);
         return SharedBuffer::create(nsData.get());
     }
@@ -438,11 +434,7 @@
     if (!item)
         return { };
 
-    auto platformType = modernPasteboardTypeForWebSafeMIMEType(type);
-    if (!platformType)
-        return { };
-
-    return [item stringForType:platformType];
+    return [item stringForType:type];
 }
 
 URL PlatformPasteboard::readURL(size_t index, String& title) const
diff --git a/Source/WebCore/platform/win/PasteboardWin.cpp b/Source/WebCore/platform/win/PasteboardWin.cpp
index d261c21..45a37ca 100644
--- a/Source/WebCore/platform/win/PasteboardWin.cpp
+++ b/Source/WebCore/platform/win/PasteboardWin.cpp
@@ -48,6 +48,7 @@
 #include "TextEncoding.h"
 #include "WebCoreInstanceHandle.h"
 #include "markup.h"
+#include <wtf/Optional.h>
 #include <wtf/URL.h>
 #include <wtf/WindowsExtras.h>
 #include <wtf/text/CString.h>
@@ -788,7 +789,7 @@
     return ::IsClipboardFormatAvailable(WebSmartPasteFormat);
 }
 
-void Pasteboard::read(PasteboardPlainText& text)
+void Pasteboard::read(PasteboardPlainText& text, Optional<size_t>)
 {
     if (::IsClipboardFormatAvailable(CF_UNICODETEXT) && ::OpenClipboard(m_owner)) {
         if (HANDLE cbData = ::GetClipboardData(CF_UNICODETEXT)) {
@@ -1073,7 +1074,7 @@
 {
 }
 
-void Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy)
+void Pasteboard::read(PasteboardWebContentReader&, WebContentReadingPolicy, Optional<size_t>)
 {
 }
 
diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
index 2dc3ce3..d68e3e9 100644
--- a/Source/WebKit/ChangeLog
+++ b/Source/WebKit/ChangeLog
@@ -1,3 +1,19 @@
+2019-10-18  Wenson Hsieh  <wenson_hsieh@apple.com>
+
+        [Clipboard API] Refactor Pasteboard::read() to take an optional item index
+        https://bugs.webkit.org/show_bug.cgi?id=203161
+
+        Reviewed by Tim Horton.
+
+        * Shared/mac/PasteboardTypes.mm:
+        (WebKit::PasteboardTypes::forEditing):
+        (WebKit::PasteboardTypes::forSelection):
+
+        Support "com.apple.webarchive" alongside the private "Apple Web Archive pasteboard type".
+
+        * UIProcess/Cocoa/WebViewImpl.mm:
+        (WebKit::WebViewImpl::setPromisedDataForImage):
+
 2019-10-18  Ryosuke Niwa  <rniwa@webkit.org>
 
         [iOS] REGRESSION(r251269): fast/events/ios/rotation/do-not-shrink-to-fit-content-after-rotation.html and fast/events/ios/rotation/layout-viewport-during-safari-type-rotation.html fail
diff --git a/Source/WebKit/Shared/mac/PasteboardTypes.mm b/Source/WebKit/Shared/mac/PasteboardTypes.mm
index 712f9d7..7013281 100644
--- a/Source/WebKit/Shared/mac/PasteboardTypes.mm
+++ b/Source/WebKit/Shared/mac/PasteboardTypes.mm
@@ -46,7 +46,7 @@
     
 NSArray* PasteboardTypes::forEditing()
 {
-    static NSArray *types = retain([NSArray arrayWithObjects:WebArchivePboardType, WebCore::legacyHTMLPasteboardType(), WebCore::legacyFilenamesPasteboardType(), WebCore::legacyTIFFPasteboardType(), WebCore::legacyPDFPasteboardType(),
+    static NSArray *types = retain([NSArray arrayWithObjects:WebArchivePboardType, (__bridge NSString *)kUTTypeWebArchive, WebCore::legacyHTMLPasteboardType(), WebCore::legacyFilenamesPasteboardType(), WebCore::legacyTIFFPasteboardType(), WebCore::legacyPDFPasteboardType(),
         WebCore::legacyURLPasteboardType(), WebCore::legacyRTFDPasteboardType(), WebCore::legacyRTFPasteboardType(), WebCore::legacyStringPasteboardType(), WebCore::legacyColorPasteboardType(), (__bridge NSString *)kUTTypePNG, nil]);
     return types;
 }
@@ -71,7 +71,7 @@
 
 NSArray* PasteboardTypes::forSelection()
 {
-    static NSArray *types = retain([NSArray arrayWithObjects:WebArchivePboardType, WebCore::legacyRTFDPasteboardType(), WebCore::legacyRTFPasteboardType(), WebCore::legacyStringPasteboardType(), nil]);
+    static NSArray *types = retain([NSArray arrayWithObjects:WebArchivePboardType, (__bridge NSString *)kUTTypeWebArchive, WebCore::legacyRTFDPasteboardType(), WebCore::legacyRTFPasteboardType(), WebCore::legacyStringPasteboardType(), nil]);
     return types;
 }
     
diff --git a/Source/WebKit/UIProcess/Cocoa/WebViewImpl.mm b/Source/WebKit/UIProcess/Cocoa/WebViewImpl.mm
index 75e19ae..6575da6 100644
--- a/Source/WebKit/UIProcess/Cocoa/WebViewImpl.mm
+++ b/Source/WebKit/UIProcess/Cocoa/WebViewImpl.mm
@@ -4218,8 +4218,11 @@
     [pasteboard declareTypes:types.get() owner:m_view.getAutoreleased()];
     setFileAndURLTypes(filename, extension, title, url, visibleURL, pasteboard);
 
-    if (archiveBuffer)
-        [pasteboard setData:archiveBuffer->createNSData().get() forType:PasteboardTypes::WebArchivePboardType];
+    if (archiveBuffer) {
+        auto nsData = archiveBuffer->createNSData();
+        [pasteboard setData:nsData.get() forType:(__bridge NSString *)kUTTypeWebArchive];
+        [pasteboard setData:nsData.get() forType:PasteboardTypes::WebArchivePboardType];
+    }
 
     m_promisedImage = image;
 }
diff --git a/Tools/ChangeLog b/Tools/ChangeLog
index ea20e67..d0819d7 100644
--- a/Tools/ChangeLog
+++ b/Tools/ChangeLog
@@ -1,3 +1,17 @@
+2019-10-18  Wenson Hsieh  <wenson_hsieh@apple.com>
+
+        [Clipboard API] Refactor Pasteboard::read() to take an optional item index
+        https://bugs.webkit.org/show_bug.cgi?id=203161
+
+        Reviewed by Tim Horton.
+
+        Add a couple of new API tests to verify that the web archive type identifier ("com.apple.webarchive") is (1)
+        written to the pasteboard when copying a rich text selection, and (2) is read when attempting to paste web
+        content.
+
+        * TestWebKitAPI/Tests/WebKitCocoa/CopyHTML.mm:
+        * TestWebKitAPI/Tests/WebKitCocoa/PasteWebArchive.mm:
+
 2019-10-18  Jonathan Bedard  <jbedard@apple.com>
 
         Python 3: Add support in webkitpy.common.watchlist
diff --git a/Tools/TestWebKitAPI/Tests/WebKitCocoa/CopyHTML.mm b/Tools/TestWebKitAPI/Tests/WebKitCocoa/CopyHTML.mm
index 312c0d9..413ee3d 100644
--- a/Tools/TestWebKitAPI/Tests/WebKitCocoa/CopyHTML.mm
+++ b/Tools/TestWebKitAPI/Tests/WebKitCocoa/CopyHTML.mm
@@ -87,4 +87,26 @@
     EXPECT_FALSE(htmlInNativePasteboard.contains("dangerousCode"));
 }
 
+#if PLATFORM(MAC)
+
+TEST(CopyHTML, ItemTypesWhenCopyingWebContent)
+{
+    auto webView = createWebViewWithCustomPasteboardDataEnabled();
+    [webView synchronouslyLoadHTMLString:@"<strong style='color: rgb(255, 0, 0);'>This is some text to copy.</strong>"];
+    [webView stringByEvaluatingJavaScript:@"getSelection().selectAllChildren(document.body)"];
+    [webView copy:nil];
+    [webView waitForNextPresentationUpdate];
+
+    NSArray<NSPasteboardItem *> *items = NSPasteboard.generalPasteboard.pasteboardItems;
+    EXPECT_EQ(1U, items.count);
+
+    NSArray<NSPasteboardType> *types = items.firstObject.types;
+    EXPECT_TRUE([types containsObject:(__bridge NSString *)kUTTypeWebArchive]);
+    EXPECT_TRUE([types containsObject:(__bridge NSString *)NSPasteboardTypeRTF]);
+    EXPECT_TRUE([types containsObject:(__bridge NSString *)NSPasteboardTypeString]);
+    EXPECT_TRUE([types containsObject:(__bridge NSString *)NSPasteboardTypeHTML]);
+}
+
 #endif // PLATFORM(MAC)
+
+#endif // PLATFORM(COCOA)
diff --git a/Tools/TestWebKitAPI/Tests/WebKitCocoa/PasteWebArchive.mm b/Tools/TestWebKitAPI/Tests/WebKitCocoa/PasteWebArchive.mm
index 3f5b6f1..b785f5c 100644
--- a/Tools/TestWebKitAPI/Tests/WebKitCocoa/PasteWebArchive.mm
+++ b/Tools/TestWebKitAPI/Tests/WebKitCocoa/PasteWebArchive.mm
@@ -240,6 +240,28 @@
     EXPECT_WK_STREQ("rgb(255, 0, 0)", [webView stringByEvaluatingJavaScript:@"document.queryCommandValue('foreColor')"]);
 }
 
+TEST(PasteWebArchive, WebArchiveTypeIdentifier)
+{
+    NSURL *url = [NSURL URLWithString:@"file:///some-file.html"];
+    NSString *markup = @"<strong style='color: rgb(255, 0, 0);'>This is some text to copy.</strong>";
+
+    auto mainResource = adoptNS([[WebResource alloc] initWithData:[markup dataUsingEncoding:NSUTF8StringEncoding] URL:url MIMEType:@"text/html" textEncodingName:@"utf-8" frameName:nil]);
+    auto archive = adoptNS([[WebArchive alloc] initWithMainResource:mainResource.get() subresources:nil subframeArchives:nil]);
+
+    NSPasteboard *pasteboard = [NSPasteboard generalPasteboard];
+    [pasteboard declareTypes:[NSArray arrayWithObject:(__bridge NSString *)kUTTypeWebArchive] owner:nil];
+    [pasteboard setData:[archive data] forType:(__bridge NSString *)kUTTypeWebArchive];
+
+    auto webView = createWebViewWithCustomPasteboardDataEnabled();
+    [webView synchronouslyLoadTestPageNamed:@"paste-rtfd"];
+    [webView paste:nil];
+
+    EXPECT_WK_STREQ("[\"text/html\"]", [webView stringByEvaluatingJavaScript:@"JSON.stringify(clipboardData.types)"]);
+    [webView evaluateJavaScript:@"docment.body.innerHTML = clipboardData.values[0]" completionHandler:nil];
+    EXPECT_WK_STREQ("This is some text to copy.", [webView stringByEvaluatingJavaScript:@"document.querySelector('strong').textContent"]);
+    EXPECT_WK_STREQ("rgb(255, 0, 0)", [webView stringByEvaluatingJavaScript:@"getComputedStyle(document.querySelector('strong')).color"]);
+}
+
 #endif // PLATFORM(MAC)