Don't expose a LayerImpl reference 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..d9f52733e6c6340ba02f2c4ddf2457a2bec4f35e 100644
--- a/third_party/WebKit/Source/core/dom/CompositorProxy.h
+++ b/third_party/WebKit/Source/core/dom/CompositorProxy.h
@@ -37,6 +37,7 @@ class CORE_EXPORT CompositorProxy final
 
   DEFINE_INLINE_TRACE() {}
 
+  uint64_t proxyId() const { return (uint64_t)this; }

[smcgruer, 2017/03/20 14:31:50]

I think this should probably be a static uint64_t that is incremented and
assigned in the constructor, unless flackr has a better idea of how to assign an
id to each proxy.

[Scott Funkenhauser, 2017/03/21 19:31:11]

Done.

   uint64_t elementId() const { return m_elementId; }
   uint32_t compositorMutableProperties() const {
     return m_compositorMutableProperties;