Preparation for enabling slimming paint synchronized painting

third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp

Index: third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp b/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
index 92a5678076aae0a620e5187d444f6b1ad2b0eae2..e9f41b22e32f0aaaac61a66746f54b54af292c8e 100644
--- a/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
+++ b/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
@@ -301,6 +301,15 @@ void GraphicsLayer::paintIfNeeded(GraphicsContext& context)
     if (firstPaintInvalidationTrackingEnabled())
         m_debugInfo.clearAnnotatedInvalidateRects();
     incrementPaintCount();
+#ifndef NDEBUG
+    if (m_paintController && contentsOpaque() && s_drawDebugRedFill) {
+        FloatRect rect(FloatPoint(), size());
+        if (!DrawingRecorder::useCachedDrawingIfPossible(context, *this, DisplayItem::DebugRedFill)) {
+            DrawingRecorder recorder(context, *this, DisplayItem::DebugRedFill, rect);
+            context.fillRect(rect, SK_ColorRED);
+        }
+    }
+#endif
     m_client->paintContentsIfNeeded(this, context, m_paintingPhase);
     notifyFirstPaintToClient();
 }