Avoid exposing cc::Layer tree to CompositorProxy

third_party/WebKit/Source/core/dom/CompositorProxy.h

Index: third_party/WebKit/Source/core/dom/CompositorProxy.h
diff --git a/third_party/WebKit/Source/core/dom/CompositorProxy.h b/third_party/WebKit/Source/core/dom/CompositorProxy.h
index 37efc8446b9c7ccaee8fc3a31b967010ae1fd374..785c26e57418d81e09926e8f3ce70bd8f64a1ca2 100644
--- a/third_party/WebKit/Source/core/dom/CompositorProxy.h
+++ b/third_party/WebKit/Source/core/dom/CompositorProxy.h
@@ -38,6 +38,7 @@ class CORE_EXPORT CompositorProxy final
   DEFINE_INLINE_TRACE() {}
 
   uint64_t elementId() const { return m_elementId; }
+  uint64_t proxyId() const { return m_proxyId; }
   uint32_t compositorMutableProperties() const {
     return m_compositorMutableProperties;
   }
@@ -72,6 +73,7 @@ class CORE_EXPORT CompositorProxy final
   void disconnectInternal();
 
   const uint64_t m_elementId = 0;
+  const uint64_t m_proxyId = 0;

[flackr, 2017/04/03 17:09:19]

Do we need proxyId? Can we not key off of elementId?

[smcgruer, 2017/04/03 17:57:31]

Is there not a N:1 relationship between CompositorProxy and elementId?  As an
element can be involved in multiple CompositorWorker animations, creating a
CompositorProxy for it in each animation?

[flackr, 2017/04/11 17:51:36]

At least there is in the current implementation where you can create many
CompositorProxy objects for a single element. Acknowledged.

   const uint32_t m_compositorMutableProperties = 0;
 
   bool m_connected = true;