TextManipulationController range of paragraph may be wrong after r262601
https://bugs.webkit.org/show_bug.cgi?id=212874

Reviewed by Wenson Hsieh.

Source/WebCore:

Start and end position of item are not properly set in r262601.

Test: TextManipulation.CompleteTextManipulationSuccedsWhenContentOutOfParagraphIsAdded

* editing/TextManipulationController.cpp:
(WebCore::TextManipulationController::addItemIfPossible):

Tools:

* TestWebKitAPI/Tests/WebKitCocoa/TextManipulation.mm:
(TestWebKitAPI::TEST):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@262780 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/WebCore/editing/TextManipulationController.cpp b/Source/WebCore/editing/TextManipulationController.cpp
index a2b2002..08479d1b 100644
--- a/Source/WebCore/editing/TextManipulationController.cpp
+++ b/Source/WebCore/editing/TextManipulationController.cpp
@@ -398,8 +398,9 @@
     if (index == end)
         return;
 
-    auto startPosition = firstPositionInOrBeforeNode(units.first().node.ptr());
-    auto endPosition = positionAfterNode(units.last().node.ptr());
+    ASSERT(end);
+    auto startPosition = firstPositionInOrBeforeNode(units[index].node.ptr());
+    auto endPosition = positionAfterNode(units[end - 1].node.ptr());
     Vector<ManipulationToken> tokens;
     for (; index < end; ++index)
         tokens.appendVector(WTFMove(units[index].tokens));