Merge 170403 - Use a lock to deal with concurrent access to the m_evictedBackings

cc/thread_proxy.h

Index: cc/thread_proxy.h
diff --git a/cc/thread_proxy.h b/cc/thread_proxy.h
index 1c57dfbb119c1635a556b06f67535218929b65fe..f2ba61117d452550c965a2dc7c7e5f0f92e9104b 100644
--- a/cc/thread_proxy.h
+++ b/cc/thread_proxy.h
@@ -89,7 +89,6 @@ private:
         base::TimeTicks monotonicFrameBeginTime;
         scoped_ptr<ScrollAndScaleSet> scrollInfo;
         WebKit::WebTransformationMatrix implTransform;
-        PrioritizedTextureManager::BackingList evictedContentsTexturesBackings;
         size_t memoryAllocationLimitBytes;
     };
     scoped_ptr<BeginFrameAndCommitState> m_pendingBeginFrameRequest;