Revert of Make GraphicsLayer the DisplayItemClient for scrollbars composited via PaintLayerCompositor.

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

Index: third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp b/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
index e7ca1485c27c4b6ba68135c76d94b28e905c38d0..26f74ec8bb84d91ae85a2125af480ac43b364989 100644
--- a/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
@@ -56,13 +56,11 @@
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/ScriptForbiddenScope.h"
 #include "platform/TraceEvent.h"
-#include "platform/geometry/FloatRect.h"
 #include "platform/graphics/CompositorMutableProperties.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/CullRect.h"
 #include "platform/graphics/paint/DrawingRecorder.h"
 #include "platform/graphics/paint/PaintController.h"
-#include "platform/graphics/paint/SkPictureBuilder.h"
 #include "platform/graphics/paint/TransformDisplayItem.h"
 
 namespace blink {
@@ -793,8 +791,11 @@
     return layer->stackingNode()->hasNegativeZOrderList();
 }
 
-static void paintScrollbar(const GraphicsLayer* graphicsLayer, const Scrollbar* scrollbar, GraphicsContext& context, const IntRect& clip)
-{
+static void paintScrollbar(const Scrollbar* scrollbar, GraphicsContext& context, const IntRect& clip)
+{
+    if (!scrollbar)
+        return;
+
     // Frame scrollbars are painted in the space of the containing frame, not the local space of the scrollbar.
     const IntPoint& paintOffset = scrollbar->frameRect().location();
     IntRect transformedClip = clip;
@@ -803,6 +804,7 @@
     AffineTransform translation;
     translation.translate(-paintOffset.x(), -paintOffset.y());
     TransformRecorder transformRecorder(context, *scrollbar, translation);
+
     scrollbar->paint(context, CullRect(transformedClip));
 }
 
@@ -813,37 +815,12 @@
 
 void PaintLayerCompositor::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase, const IntRect& interestRect) const
 {
-    const Scrollbar* scrollbar = graphicsLayerToScrollbar(graphicsLayer);
-    if (!scrollbar && graphicsLayer != layerForScrollCorner())
-        return;
-
-    if (DrawingRecorder::useCachedDrawingIfPossible(context, *graphicsLayer, DisplayItem::ScrollbarCompositedScrollbar))
-        return;
-
-    FloatRect layerBounds(FloatPoint(), graphicsLayer->size());
-    SkPictureBuilder pictureBuilder(layerBounds, nullptr, &context);
-
-    if (scrollbar)
-        paintScrollbar(graphicsLayer, scrollbar, pictureBuilder.context(), interestRect);
-    else
-        FramePainter(*m_layoutView.frameView()).paintScrollCorner(pictureBuilder.context(), interestRect);
-
-    // Replay the painted scrollbar content with the GraphicsLayer backing as the DisplayItemClient
-    // in order for the resulting DrawingDisplayItem to produce the correct visualRect (i.e., the
-    // bounds of the involved GraphicsLayer).
-    DrawingRecorder drawingRecorder(context, *graphicsLayer, DisplayItem::ScrollbarCompositedScrollbar, layerBounds);
-    pictureBuilder.endRecording()->playback(context.canvas());
-}
-
-Scrollbar* PaintLayerCompositor::graphicsLayerToScrollbar(const GraphicsLayer* graphicsLayer) const
-{
-    if (graphicsLayer == layerForHorizontalScrollbar()) {
-        return m_layoutView.frameView()->horizontalScrollbar();
-    }
-    if (graphicsLayer == layerForVerticalScrollbar()) {
-        return m_layoutView.frameView()->verticalScrollbar();
-    }
-    return nullptr;
+    if (graphicsLayer == layerForHorizontalScrollbar())
+        paintScrollbar(m_layoutView.frameView()->horizontalScrollbar(), context, interestRect);
+    else if (graphicsLayer == layerForVerticalScrollbar())
+        paintScrollbar(m_layoutView.frameView()->verticalScrollbar(), context, interestRect);
+    else if (graphicsLayer == layerForScrollCorner())
+        FramePainter(*m_layoutView.frameView()).paintScrollCorner(context, interestRect);
 }
 
 bool PaintLayerCompositor::supportsFixedRootBackgroundCompositing() const