Don't expose a LayerImpl reference to CompositorProxy.

third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h

Index: third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h
diff --git a/third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h b/third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h
index 114967af10efd33819dc3a9b180a4c876bd38367..2810019b1d09d990305ef1bc2e3c9b56ea72e1f8 100644
--- a/third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h
+++ b/third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h
@@ -5,16 +5,19 @@
 #ifndef CompositorMutatorClient_h
 #define CompositorMutatorClient_h
 
+#include <map>
+#include <memory>
 #include "platform/PlatformExport.h"
+#include "platform/graphics/CompositorMutableProperties.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/WebCompositorMutatorClient.h"
-#include <memory>
 
 namespace blink {
 
 class CompositorMutator;
 struct CompositorMutations;
 class CompositorMutationsTarget;
+class CompositorMutation;
 
 class PLATFORM_EXPORT CompositorMutatorClient
     : public WebCompositorMutatorClient {
@@ -23,6 +26,10 @@ class PLATFORM_EXPORT CompositorMutatorClient
   virtual ~CompositorMutatorClient();
 
   void setNeedsMutate();
+  void registerCompositorProxy(uint64_t proxyId,
+                               uint64_t elementId,
+                               uint32_t mutableProperties);
+  void unregisterCompositorProxy(uint64_t proxyId);
 
   // cc::LayerTreeMutator
   bool Mutate(base::TimeTicks monotonicTime, cc::LayerTreeImpl*) override;
@@ -34,8 +41,13 @@ class PLATFORM_EXPORT CompositorMutatorClient
   void setMutationsForTesting(std::unique_ptr<CompositorMutations>);
 
  private:
+  void snapshotLayerTree(const cc::LayerTreeImpl*,
+                         ProxyCompositorMutablePropertiesMap*) const;
+  void updateMutations(uint64_t elementId, std::unique_ptr<CompositorMutation>);
+
   cc::LayerTreeMutatorClient* m_client;
   CompositorMutationsTarget* m_mutationsTarget;
+  std::map<uint64_t, std::pair<uint64_t, uint32_t>> m_inputProperties;
   // Accessed by main and compositor threads.
   CrossThreadPersistent<CompositorMutator> m_mutator;
   std::unique_ptr<CompositorMutations> m_mutations;