tree b786837449d1c78b42a3839bc3798f7878488899
parent 61519cf4ebdb258a5cd2da729649197f46bf6208
author dbates@webkit.org <dbates@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1593543940 +0000
committer dbates@webkit.org <dbates@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1593543940 +0000

[iOS] Editable regions causes ~1% slowdown in PLT5
https://bugs.webkit.org/show_bug.cgi?id=213659
<rdar://problem/64361390>

Reviewed by Simon Fraser.

Source/WebCore:

Fix the slowdown by only enabling editable region when Page::editableElementsInRect is called.

There are two parts that make computing the editable region expensive:
        1. Requires traversing descendents during painting when a normal paint may be
           able to avoid this.
        2. Can cause more event region invalidations because it extends the invalidation
           criterion to include changes to element editability.

Tests: editing/editable-region/hit-test-basic-without-editable-region.html
       editing/editable-region/iframe-without-editable-region.html
       editing/editable-region/text-field-basic-without-editable-region.html

Tests: editing/editable-region/hit-test-basic-without-editable-region.html
       editing/editable-region/iframe-without-editable-region.html
       editing/editable-region/text-field-basic-without-editable-region.html

* page/Frame.cpp:
(WebCore::Frame::invalidateContentEventRegionsIfNeeded): Check if editable region is enabled.
If it is then do what we do now. Otherwise, don't invalidate the region unless we were going
to do so anyway.
* page/Page.cpp:
(WebCore::Page::setEditableRegionEnabled): Added. Update state and then invalidate
the event region in all layers.
(WebCore::Page::shouldBuildEditableRegion const): Added. Returns whether to build the
editable region: either when Page::isEditableRegionEnabled() is true or the editable
region debug overlay is enabled.
(WebCore::Page::didFinishLoad): Turn off editable region as it may not be needed on
the new page.
* page/Page.h:
(WebCore::Page::isEditableRegionEnabled const): Added.

* rendering/EventRegion.cpp:
(WebCore::EventRegion::unite):
(WebCore::EventRegion::translate):
(WebCore::EventRegion::containsEditableElementsInRect const):
(WebCore::EventRegion::dump const):
* rendering/EventRegion.h:
(WebCore::EventRegion::hasEditableRegion const):
(WebCore::EventRegion::rectsForEditableElements const):
(WebCore::EventRegion::decode):
(WebCore::EventRegion::ensureEditableRegion):
The editable region is now an Optional<>. There will only be one if ensureEditableRegion
was called, which is only when Page::isEditableRegionEnabled() returns true.

* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::paintObject):
* rendering/RenderElement.cpp:
(WebCore::RenderElement::styleWillChange):
* rendering/RenderLayer.h:
* rendering/RenderLayerBacking.cpp:
(WebCore::RenderLayerBacking::maintainsEventRegion const):
Only do what we do now if Page::shouldBuildEditableRegion() returns true.

(WebCore::RenderLayerBacking::updateEventRegion): Instantiate the editable region, if needed.
Painting will then populate it.

* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::applyToCompositedLayerIncludingDescendants): Added.
(WebCore::RenderLayerCompositor::invalidateEventRegionForAllLayers): Added.
(WebCore::RenderLayerCompositor::clearBackingForAllLayers): Wrote in terms of applyToCompositedLayerIncludingDescendants.
(WebCore::RenderLayerCompositor::clearBackingForLayerIncludingDescendants): Deleted.
* rendering/RenderLayerCompositor.h:
* testing/InternalSettings.cpp:
(WebCore::InternalSettings::setEditableRegionEnabled):
* testing/InternalSettings.h:
* testing/InternalSettings.idl:
Add a new internal setting for testing purposes to toggle enabling/disabling editable region.

Source/WebKit:

Fix up RemoteLayerTreeViews now that the editable region is an Optional<>. Have
the UI process message the web process to enable editable region on the first
invocation of _requestTextInputContextsInRect, which is good indicator that there
would be benefit to computing it as a typical client that calls it will call it
many times.

* UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm:
(WebKit::mayContainEditableElementsInRect): Fix up the logic now that there may
be not be an editable region sent over in the last event region update. If there
isn't one then we don't know if there are editable elements in the rect of not.
So, return true, which could turn out to be a false positive if there aren't any
editable elements in the rect. The caller will have to message the web process
to find out the real answer if they want it. Just to clarify, it's OK for this
function to have false positives, but it must never have false negatives.
* WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::textInputContextsInRect): Enable editable region. If it's already
enabled then doing so again does nothing.

LayoutTests:

Add some tests to ensure the new setting works and the feature can be disabled. Note
that the setting is enabled by default to keep the current behavior. See the WebCore
ChangeLog entry for more details.

Update existings tests that need the editable region enabled to enable it now that it must
be explicitly enabled.

* editing/editable-region/fixed-and-absolute-contenteditable-scrolled.html:
* editing/editable-region/float-contenteditable.html:
* editing/editable-region/hit-test-basic-without-editable-region-expected.txt: Added.
* editing/editable-region/hit-test-basic-without-editable-region.html: Copied from LayoutTests/editing/editable-region/hit-test-basic.html.
* editing/editable-region/hit-test-basic.html:
* editing/editable-region/hit-test-editable-document-element.html:
* editing/editable-region/hit-test-fixed.html:
* editing/editable-region/hit-test-overlap.html:
* editing/editable-region/hit-test-textarea-empty-space.html:
* editing/editable-region/iframe-without-editable-region-expected.txt: Added.
* editing/editable-region/iframe-without-editable-region.html: Copied from LayoutTests/editing/editable-region/iframe.html.
* editing/editable-region/iframe.html:
* editing/editable-region/out-hanging-child-of-contenteditable.html:
* editing/editable-region/overflow-scroll-text-field-and-contenteditable.html:
* editing/editable-region/relative-inside-fixed-contenteditable-scrolled.html:
* editing/editable-region/relative-inside-transformed-contenteditable.html:
* editing/editable-region/search-field-basic.html:
* editing/editable-region/text-field-basic-without-editable-region-expected.txt: Added.
* editing/editable-region/text-field-basic-without-editable-region.html: Copied from LayoutTests/editing/editable-region/text-field-basic.html.
* editing/editable-region/text-field-basic.html:
* editing/editable-region/text-field-inside-composited-negative-z-index-layer.html:
* editing/editable-region/textarea-basic.html:
* editing/editable-region/transformed-scrolled-on-top-of-fixed-contenteditables.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@263762 268f45cc-cd09-0410-ab3c-d52691b4dbfc