compositor-worker: plumb element id and mutable properties

cc/blink/web_layer_impl.h

Index: cc/blink/web_layer_impl.h
diff --git a/cc/blink/web_layer_impl.h b/cc/blink/web_layer_impl.h
index 44ef02e2210c8b70c015ac1ed6958ab2adbc1297..bc49ab60608de50fed40f1f38e86278b3c6c271e 100644
--- a/cc/blink/web_layer_impl.h
+++ b/cc/blink/web_layer_impl.h
@@ -146,6 +146,10 @@ class WebLayerImpl : public blink::WebLayer, public cc::LayerClient {
   void setScrollClient(blink::WebLayerScrollClient* client) override;
   bool isOrphan() const override;
   void setWebLayerClient(blink::WebLayerClient* client) override;
+  void setElementId(uint64_t id) override;
+  uint64_t elementId() const override;
+  void setMutableProperties(uint32_t properties) override;
+  uint32_t mutableProperties() const override;
 
   // LayerClient implementation.
   scoped_refptr<base::trace_event::ConvertableToTraceFormat> TakeDebugInfo()