Add CompositingReasons to compositor layer types.

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index 1798b93566a96b7bf0330e9d12508c16ddd69234..00fcb3419367e8c1a05e7dd85322d18abd339282 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -25,6 +25,7 @@
 #include "cc/quads/shared_quad_state.h"
 #include "cc/resources/resource_provider.h"
 #include "skia/ext/refptr.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebCompositingReasons.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebFilterOperations.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
@@ -205,6 +206,13 @@ class CC_EXPORT LayerImpl : LayerAnimationValueObserver {
   void SetDebugName(const std::string& debug_name) { debug_name_ = debug_name; }
   std::string debug_name() const { return debug_name_; }
 
+  void SetCompositingReasons(WebKit::WebCompositingReasons reasons) {
+      compositing_reasons_ = reasons;
+  }
+  WebKit::WebCompositingReasons compositing_reasons() const {
+      return compositing_reasons_;
+  }
+
   bool ShowDebugBorders() const;
 
   // These invalidate the host's render surface layer list.  The caller
@@ -514,6 +522,7 @@ class CC_EXPORT LayerImpl : LayerAnimationValueObserver {
 
   // Debug layer name.
   std::string debug_name_;
+  WebKit::WebCompositingReasons compositing_reasons_;
 
   WebKit::WebFilterOperations filters_;
   WebKit::WebFilterOperations background_filters_;