[compositorworker] compositor proxy mutation updates underlying layers

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

 // Copyright 2016 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 CompositorMutator_h
 #define CompositorMutator_h
 
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
+class CompositorMutableStateProvider;
+
 class CompositorMutator : public GarbageCollectedFinalized<CompositorMutator> {
 public:
     virtual ~CompositorMutator() {}
 
     DEFINE_INLINE_VIRTUAL_TRACE() {}
 
     // Called from compositor thread to run the animation frame callbacks from all
     // connected CompositorWorkers.
     // Returns true if any animation callbacks requested an animation frame
     // (i.e. should be reinvoked next frame).
-    virtual bool mutate(double monotonicTimeNow) = 0;
+    virtual bool mutate(double monotonicTimeNow, CompositorMutableStateProvider*) = 0;
 };
 
 } // namespace blink
 
 #endif // CompositorMutator_h