Restore the "don't flatten scrolling content layer" logic.

This restores some logic removed in https://codereview.chromium.org/1030323005/.
This seems to change some of Blink's behaviour back, and will hopefully resolve issues with unclipped render surfaces.

BUG=521768

Review URL: https://codereview.chromium.org/1300213004

git-svn-id: svn://svn.chromium.org/blink/trunk@201138 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -659,6 +659,53 @@ crbug.com/381684 [ Win Android Mac ] fonts/family-fallback-gardiner.html [ Skip
 
 crbug.com/467635 fast/dom/HTMLImageElement/image-sizes-meta-viewport.html [ Skip ]
 
+crbug.com/521768 compositing/layer-creation/fixed-position-in-fixed-overflow.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/layer-creation/fixed-position-nonscrollable-body-mismatch-containers.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/clear-scroll-parent.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/composited-scrolling-paint-phases.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/content-gains-scrollbars.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/overflow-scrollbar-layers.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/reparented-scrollbars-non-sc-anc.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/scroll-parent-absolute.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/scroll-parent-with-non-stacking-context-composited-ancestor.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/scrolling-content-clip-to-viewport.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/scrolling-without-painting.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/selection-gaps-after-removing-scrolling-contents.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/selection-gaps-toggling-with-scrolling-contents.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/selection-gaps-toggling.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/textarea-scroll-touch.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/universal-accelerated-overflow-scroll.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/overflow/updating-scrolling-content.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/repaint/should-not-clip-composited-overflow-scrolling-layer.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/scrollbars/nested-overlay-scrollbars.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/squashing/composited-bounds-for-negative-z.html [ NeedsRebaseline ]
+crbug.com/521768 compositing/update-paint-phases.html [ NeedsRebaseline ]
+crbug.com/521768 fast/repaint/overflow-move-after-scroll.html [ NeedsRebaseline ]
+crbug.com/521768 fast/repaint/overflow-scroll-after-move.html [ NeedsRebaseline ]
+crbug.com/521768 paint/invalidation/invalidate-after-composited-scroll.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/clear-scroll-parent.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/composited-scrolling-paint-phases.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/content-gains-scrollbars.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-auto-with-touch-toggle.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-auto-with-touch.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-overlay-with-touch.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-scrollbar-layers.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/reparented-scrollbars-non-sc-anc.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/scroll-parent-absolute.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/scroll-parent-with-non-stacking-context-composited-ancestor.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/scrolling-content-clip-to-viewport.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/scrolling-without-painting.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/selection-gaps-after-removing-scrolling-contents.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/selection-gaps-toggling-with-scrolling-contents.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/selection-gaps-toggling.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/text-color-change.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/text-match-highlight.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/textarea-scroll-touch.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/universal-accelerated-overflow-scroll.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/updating-scrolling-container-and-content.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/updating-scrolling-container.html [ NeedsRebaseline ]
+crbug.com/521768 virtual/prefer_compositing_to_lcd_text/compositing/overflow/updating-scrolling-content.html [ NeedsRebaseline ]
+
 crbug.com/517898 [ SnowLeopard Debug ] fast/text/international/bidi-neutral-run.html [ Crash ]
 
 # crbug.com/396823 [ Mac ] fast/multicol/multicol-with-child-renderLayer-for-input.html [ ImageOnlyFailure ]
@@ -974,7 +1021,6 @@ crbug.com/509025 [ Yosemite ] compositing/layer-creation/should-invoke-deferred-
 crbug.com/509025 [ Yosemite ] compositing/overflow/fixed-scroll-in-empty-root-layer.html [ Failure ]
 crbug.com/509025 [ Yosemite ] compositing/overflow/text-color-change.html [ Failure ]
 crbug.com/509025 [ Yosemite ] compositing/overflow/text-match-highlight.html [ Failure ]
-crbug.com/509025 [ Yosemite ] compositing/overflow/textarea-scroll-touch.html [ Failure ]
 crbug.com/509025 [ Yosemite ] compositing/overflow/updating-scrolling-container-and-content.html [ Failure ]
 crbug.com/509025 [ Yosemite ] compositing/overflow/updating-scrolling-container.html [ Failure ]
 # TODO(chrishtr): uncomment/inspect rebaseline of this after fixing crbug.com/516016
@@ -1014,7 +1060,6 @@ crbug.com/509025 [ Yosemite ] paint/invalidation/animated-gif.html [ Failure ]
 crbug.com/509025 [ Yosemite ] svg/custom/absolute-sized-content-with-resources.xhtml [ Failure ]
 crbug.com/509025 [ Yosemite ] svg/custom/bug78807.svg [ Failure ]
 crbug.com/509025 [ Yosemite ] svg/text/text-rescale.html [ Failure ]
-crbug.com/509025 [ Yosemite ] virtual/prefer_compositing_to_lcd_text/compositing/overflow/textarea-scroll-touch.html [ Failure ]
 crbug.com/509025 [ Yosemite ] compositing/geometry/fixed-position-iframe-composited-page-scale-down.html [ ImageOnlyFailure ]
 crbug.com/509025 [ Yosemite ] compositing/geometry/fixed-position-iframe-composited-page-scale.html [ ImageOnlyFailure ]
 crbug.com/509025 [ Yosemite ] compositing/iframes/iframe-copy-on-scroll.html [ ImageOnlyFailure ]

third_party/WebKit/Source/core/layout/compositing/CompositedDeprecatedPaintLayerMapping.cpp

@@ -1471,6 +1471,16 @@ void CompositedDeprecatedPaintLayerMapping::updateShouldFlattenTransform()
             layer->setShouldFlattenTransform(false);
         }, ApplyToChildContainingLayers);
     }
+
+    // Regardless, mark the scrolling contents layer and scrolling block
+    // selection layer (if they exist) as not flattening. Having them flatten
+    // causes unclipped render surfaces which cause bugs.
+    // http://crbug.com/521768
+    if (hasScrollingLayer()) {
+        m_scrollingContentsLayer->setShouldFlattenTransform(false);
+        if (m_scrollingBlockSelectionLayer)
+            m_scrollingBlockSelectionLayer->setShouldFlattenTransform(false);
+    }
 }
 
 bool CompositedDeprecatedPaintLayerMapping::updateForegroundLayer(bool needsForegroundLayer)