Add CCDelegatingRenderer, and corresponding IPCs

cc/ScrollbarLayerChromium.cpp

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "ScrollbarLayerChromium.h"
 
@@ skipping 232 matching lines @@
     TextureUploader::Parameters upload = { texture, rect, destOffset };
     queue.appendFullUpload(upload);
 }
 
 
 void ScrollbarLayerChromium::setTexturePriorities(const CCPriorityCalculator&)
 {
     if (contentBounds().isEmpty())
         return;
 
+    if (!m_updateRect.isEmpty() /* && ubercomp */) {
+        m_backTrack.clear();
+        m_foreTrack.clear();
+        m_thumb.clear();
+    }
     createTextureUpdaterIfNeeded();
 
     bool drawsToRoot = !renderTarget()->parent();
     if (m_backTrack) {
         m_backTrack->texture()->setDimensions(contentBounds(), m_textureFormat);
         m_backTrack->texture()->setRequestPriority(CCPriorityCalculator::uiPriority(drawsToRoot));
     }
     if (m_foreTrack) {
         m_foreTrack->texture()->setDimensions(contentBounds(), m_textureFormat);
         m_foreTrack->texture()->setRequestPriority(CCPriorityCalculator::uiPriority(drawsToRoot));
@@ skipping 20 matching lines @@
 
     // Consider the thumb to be at the origin when painting.
     WebKit::WebRect thumbRect = m_geometry->thumbRect(m_scrollbar.get());
     IntRect originThumbRect = layerRectToContentRect(WebKit::WebRect(0, 0, thumbRect.width, thumbRect.height));
     if (!originThumbRect.isEmpty())
         updatePart(m_thumbUpdater.get(), m_thumb.get(), originThumbRect, queue, stats);
 }
 
 }
 #endif // USE(ACCELERATED_COMPOSITING)