Avoid exposing cc::Layer tree 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 b543aa136cc759fb4dd068abc9c86a7ce62efc07..fae0bf4808c0486c947a4511262d231c2671dd3d 100644
--- a/third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h
+++ b/third_party/WebKit/Source/platform/graphics/CompositorMutatorClient.h
@@ -5,16 +5,21 @@
 #ifndef CompositorMutatorClient_h
 #define CompositorMutatorClient_h
 
+#include <map>
+#include <memory>
+#include <utility>
+
 #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 +28,10 @@ class PLATFORM_EXPORT CompositorMutatorClient
   virtual ~CompositorMutatorClient();
 
   void SetNeedsMutate();
+  void RegisterCompositorProxy(uint64_t proxy_id,
+                               uint64_t element_id,
+                               uint32_t mutable_properties);
+  void UnregisterCompositorProxy(uint64_t proxy_id);
 
   // cc::LayerTreeMutator
   bool Mutate(base::TimeTicks monotonic_time, cc::LayerTreeImpl*) override;
@@ -34,8 +43,19 @@ class PLATFORM_EXPORT CompositorMutatorClient
   void SetMutationsForTesting(std::unique_ptr<CompositorMutations>);
 
  private:
+  void SnapshotLayerTree(const cc::LayerTreeImpl*,
+                         ProxyCompositorMutablePropertiesMap*) const;
+  void UpdateLayerTree(cc::LayerTreeImpl*,
+                       uint64_t element_id,
+                       const CompositorMutation*);
+  void UpdateMutations(uint64_t element_id,
+                       std::unique_ptr<CompositorMutation>);
+
   cc::LayerTreeMutatorClient* client_;
   CompositorMutationsTarget* mutations_target_;
+  // Maps from a |CompositorProxy| id to a pair of the element id for that
+  // proxy, and the bitmask of properties the proxy is allowed to mutate.
+  std::map<uint64_t, std::pair<uint64_t, uint32_t>> input_properties_;
   // Accessed by main and compositor threads.
   CrossThreadPersistent<CompositorMutator> mutator_;
   std::unique_ptr<CompositorMutations> mutations_;