Don't free non-tile resources on GPU rasterization toggle

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index 6e8475a263a3d84842891f664f8d6d269e9fee82..a374750dbb75128c256164eaeadab4f399bad793 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -375,12 +375,16 @@ class CC_EXPORT LayerImpl {
   virtual void DidBeginTracing();
 
   // Release resources held by this layer. Called when the output surface
-  // that rendered this layer was lost or a rendering mode switch has occured.
+  // that rendered this layer was lost.
   virtual void ReleaseResources();
 
-  // Recreate resources that are required after they were released by a
-  // ReleaseResources call.
-  virtual void RecreateResources();
+  // Release tile resources held by this layer. Called when a rendering mode
+  // switch has occured and tiles are no longer valid.
+  virtual void ReleaseTileResources();
+
+  // Recreate tile resources held by this layer after they were released by a
+  // ReleaseTileResources call.
+  virtual void RecreateTileResources();
 
   virtual std::unique_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl);
   virtual bool IsSnapped();