Integrate r128344 and r128253 from WebKit

cc/CCLayerTreeHost.h

 // Copyright 2011 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.
 
 #ifndef CCLayerTreeHost_h
 #define CCLayerTreeHost_h
 
 #include "CCAnimationEvents.h"
 #include "CCGraphicsContext.h"
 #include "CCLayerTreeHostClient.h"
@@ skipping 173 matching lines @@
     const IntSize& deviceViewportSize() const { return m_deviceViewportSize; }
 
     void setPageScaleFactorAndLimits(float pageScaleFactor, float minPageScaleFactor, float maxPageScaleFactor);
 
     void setBackgroundColor(SkColor color) { m_backgroundColor = color; }
 
     void setHasTransparentBackground(bool transparent) { m_hasTransparentBackground = transparent; }
 
     CCPrioritizedTextureManager* contentsTextureManager() const;
 
-    void unlinkAllContentTextures();
-    void deleteUnlinkedTextures();
+    // Delete contents textures' backing resources until they use only bytesLimit bytes. This may
+    // be called on the impl thread while the main thread is running.
+    void reduceContentsTexturesMemoryOnImplThread(size_t bytesLimit, CCResourceProvider*);
+    // Retrieve the list of all contents textures' backings that have been evicted, to pass to the
+    // main thread to unlink them from their owning textures.
+    void getEvictedContentTexturesBackings(CCPrioritizedTextureManager::BackingVector&);
+    // Unlink the list of contents textures' backings from their owning textures on the main thread
+    // before updating layers.
+    void unlinkEvictedContentTexturesBackings(const CCPrioritizedTextureManager::BackingVector&);
+    // Deletes all evicted backings, unlinking them from their owning textures if needed.
+    // Returns true if this function had to unlink any backings from their owning texture when
+    // destroying them. If this was the case, the impl layer tree may contain invalid resources.
+    bool deleteEvictedContentTexturesBackings();
 
     bool visible() const { return m_visible; }
     void setVisible(bool);
 
     void startPageScaleAnimation(const IntSize& targetPosition, bool useAnchor, float scale, double durationSec);
 
     void applyScrollAndScale(const CCScrollAndScaleSet&);
 
     void startRateLimiter(WebKit::WebGraphicsContext3D*);
     void stopRateLimiter(WebKit::WebGraphicsContext3D*);
@@ skipping 78 matching lines @@
 
     TextureList m_deleteTextureAfterCommitList;
     size_t m_partialTextureUpdateRequests;
 
     static bool s_needsFilterContext;
 };
 
 }
 
 #endif