Delete CompositingUpdateAfterLayout

Rather than using a different update type, we can just mark the root as needing
its properties updated, which will cause us to update the entire tree. This CL
alone isn't a huge win, but it will let us remove
RenderLayerCompositor::m_compositingLayersNeedRebuild in the next CL.

Also, move the call to enableCompositingModeIfNeeded into the new
RenderLayerCompositor::didLayout function. This makes the sequence look a bit
silly (because we mark the dirty bit only to clear it immediately), but that's
what the code did before (albeit in a more roundabout way).

BUG=332248

Review URL: https://codereview.chromium.org/323653002

git-svn-id: svn://svn.chromium.org/blink/trunk@175738 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/frame/FrameView.cpp

@@ -970,7 +970,7 @@ void FrameView::layout(bool allowSubtree)
         adjustViewSize();
 
     layer->updateLayerPositionsAfterLayout(renderView()->layer(), updateLayerPositionFlags(layer, inSubtreeLayout, m_doFullPaintInvalidation));
-    renderView()->compositor()->setNeedsCompositingUpdate(CompositingUpdateAfterLayout);
+    renderView()->compositor()->didLayout();
 
     m_layoutCount++;
 

third_party/WebKit/Source/core/rendering/compositing/RenderLayerCompositor.cpp

@@ -257,25 +257,25 @@ void RenderLayerCompositor::updateIfNeededRecursive()
 void RenderLayerCompositor::setNeedsCompositingUpdate(CompositingUpdateType updateType)
 {
     ASSERT(updateType != CompositingUpdateNone);
-    // FIXME: Technically we only need to do this when the FrameView's isScrollable method
-    // would return a different value.
-    if (updateType == CompositingUpdateAfterLayout)
-        m_rootShouldAlwaysCompositeDirty = true;
-
-    // FIXME: This function should only set dirty bits. We shouldn't
-    // enable compositing mode here.
-    // We check needsLayout here because we don't know if we need to enable
-    // compositing mode until layout is up-to-date because we need to know
-    // if this frame scrolls.
-    if (!m_renderView.needsLayout())
-        enableCompositingModeIfNeeded();
-
     m_pendingUpdateType = std::max(m_pendingUpdateType, updateType);
-
     page()->animator().scheduleVisualUpdate();
     lifecycle().ensureStateAtMost(DocumentLifecycle::LayoutClean);
 }
 
+void RenderLayerCompositor::didLayout()
+{
+    // FIXME: Technically we only need to do this when the FrameView's
+    // isScrollable method would return a different value.
+    m_rootShouldAlwaysCompositeDirty = true;
+    enableCompositingModeIfNeeded();
+
+    // FIXME: Rather than marking the entire RenderView as dirty, we should
+    // track which RenderLayers moved during layout and only dirty those
+    // specific RenderLayers.
+    rootRenderLayer()->setNeedsToUpdateAncestorDependentProperties();
+    setNeedsCompositingUpdate(CompositingUpdateAfterCompositingInputChange);
+}
+
 #if ASSERT_ENABLED
 
 void RenderLayerCompositor::assertNoUnresolvedDirtyBits()
@@ -348,12 +348,6 @@ void RenderLayerCompositor::updateIfNeeded()
     GraphicsLayerUpdater::UpdateType graphicsLayerUpdateType = GraphicsLayerUpdater::DoNotForceUpdate;
     CompositingPropertyUpdater::UpdateType compositingPropertyUpdateType = CompositingPropertyUpdater::DoNotForceUpdate;
 
-    // FIXME: Teach non-style compositing updates how to do partial tree walks.
-    if (updateType >= CompositingUpdateAfterLayout) {
-        graphicsLayerUpdateType = GraphicsLayerUpdater::ForceUpdate;
-        compositingPropertyUpdateType = CompositingPropertyUpdater::ForceUpdate;
-    }
-
     RenderLayer* updateRoot = rootRenderLayer();
 
     Vector<RenderLayer*> layersNeedingRepaint;

third_party/WebKit/Source/core/rendering/compositing/RenderLayerCompositor.h

@@ -49,7 +49,6 @@ enum CompositingUpdateType {
     CompositingUpdateNone,
     CompositingUpdateOnCompositedScroll,
     CompositingUpdateAfterCompositingInputChange,
-    CompositingUpdateAfterLayout,
 };
 
 enum CompositingStateTransitionType {
@@ -102,6 +101,8 @@ public:
     // Used to indicate that a compositing update will be needed for the next frame that gets drawn.
     void setNeedsCompositingUpdate(CompositingUpdateType);
 
+    void didLayout();
+
     enum UpdateLayerCompositingStateOptions {
         Normal,
         UseChickenEggHacks, // Use this to trigger temporary chicken-egg hacks. See crbug.com/339892.