Unreviewed. Fix make distcheck.

* bindings/gobject/GNUmakefile.am: Do not dist generated DOM
bindings headers.
* platform/ScrollAnimatorNone.cpp: Include PlatformGestureEvent.h
only if gesture events are enabled.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@137827 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Source/WebCore: [chromium] Automatically use composited scrolling
https://bugs.webkit.org/show_bug.cgi?id=94743

Reviewed by Adrienne Walker.

We currently use the composited scrolling facilities provided by
wkb.ug/91117 if the overflow scroll block element is styled with
-webkit-overflow-scrolling: touch. Ideally, we could automatically
opt into composited scrolling if it is safe to do so. This can affect
antialiasing, so it is important that automatically opting in is only
enabled via a setting.

The way I determine if it is safe is by checking that z-ordering will
not be affected if the overflow scrollable element were promoted to a
stacking context (details below), and that clipping our scrolling
descendants will not affect rendering.

To check the first condition (that z-ordering will not be affected).
I ensure that the candidate element and all its descendants appear as a
contiguous block in the candidate's stacking context. That is, if no
other elements are 'between' any of the candidates descendants when we
sort in paint order, then we're safe. This is overly conservative,
however. We could, in future, only consider stacking problems between
elements that actually overlap.

To ensure that clipping will not cause a rendering change, I ensure
that the layer has no out of flow positioned descendant whose
containing block is not also a descendant of ours.

Test: compositing/overflow/automatically-opt-into-compositing-scrolling.html

(WebCore):
* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::RenderLayer):
(WebCore::RenderLayer::acceleratedCompositingForOverflowScrollEnabled):
(WebCore):
(WebCore::RenderLayer::updateDescendantsAreContiguousInStackingOrder):
(WebCore::RenderLayer::updateDescendantsAreContiguousInStackingOrderRecursive):
(WebCore::RenderLayer::positionNewlyCreatedOverflowControls):
(WebCore::RenderLayer::canSafelyEstablishAStackingContext):
  Returns true if the RenderLayer could become a stacking context without
  affecting the stacking order.
(WebCore::RenderLayer::updateDescendantDependentFlags):
  We now need to keep track of out of flow positioned descendants.
(WebCore::RenderLayer::addChild):
(WebCore::RenderLayer::removeChild):
(WebCore::RenderLayer::usesCompositedScrolling):
  Returns true if the layer actually is using composited scrolling.
  This function may return false, even when needsCompositedScrolling
  returns true.
(WebCore::RenderLayer::needsCompositedScrolling):
  This function returns true if we would like to use composited
  scrolling and it is safe to turn it on.
(WebCore::RenderLayer::updateNeedsCompositedScrolling):
(WebCore::RenderLayer::scrollTo):
(WebCore::RenderLayer::dirtyZOrderLists):
(WebCore::RenderLayer::dirtyNormalFlowList):
  Since these could affect opting into composited scrolling, we must
  request that the RenderLayerCompositor reevaluate compositing.
(WebCore::RenderLayer::updateLayerListsIfNeeded):
  We call updateCanSafelyEstablishStackingContext here, if necessary.
(WebCore::RenderLayer::shouldBeNormalFlowOnly):
(WebCore::RenderLayer::shouldBeSelfPaintingLayer):
  usesCompositedScrolling -> needsCompositedScrolling
(WebCore::RenderLayer::setAncestorChainHasOutOfFlowPositionedDescendant):
(WebCore::RenderLayer::dirtyAncestorChainHasOutOfFlowPositionedDescendantStatus):
(WebCore::RenderLayer::updateOutOfFlowPositioned):
  Dirties and sets the out of flow positioned descendant state.
(WebCore::RenderLayer::styleChanged):
* rendering/RenderLayer.h:
(RenderLayer):
(WebCore::RenderLayer::hasOutOfFlowPositionedDescendant):
* rendering/RenderLayerBacking.cpp:
(WebCore::layerOrAncestorIsTransformedOrUsingCompositedScrolling):
(WebCore::RenderLayerBacking::updateGraphicsLayerConfiguration):
(WebCore::RenderLayerBacking::updateGraphicsLayerGeometry):
(WebCore::RenderLayerBacking::hasUnpositionedOverflowControlsLayers):
(WebCore):
* rendering/RenderLayerBacking.h:
(RenderLayerBacking):
* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::rebuildCompositingLayerTree):
(WebCore::RenderLayerCompositor::requiresCompositingForOverflowScrolling):
* rendering/RenderLayerCompositor.h:
(WebCore::RenderLayerCompositor::setShouldReevaluateCompositingAfterLayout):
* testing/InternalSettings.cpp:
(WebCore::InternalSettings::setEnableCompositingForOverflowScroll):
  Allows enabling the setting in layout tests.
(WebCore):
* testing/InternalSettings.h:
(InternalSettings):
* testing/InternalSettings.idl:

LayoutTests: Automatically use composited scrolling
https://bugs.webkit.org/show_bug.cgi?id=94743

Reviewed by Adrienne Walker.

Tests various configurations of elements to ensure that we only automatically opt into
composited scrolling when it is safe to do so.

* compositing/overflow/automatically-opt-into-composited-scrolling-expected.txt: Added.
* compositing/overflow/automatically-opt-into-composited-scrolling.html: Added.
* platform/chromium/TestExpectations:
 The test platform/chromium/virtual/gpu/compositedscrolling/scrollbars/custom-scrollbar-with-incomplete-style.html
 is failing due to wkb.ug/103156

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@137828 268f45cc-cd09-0410-ab3c-d52691b4dbfc