Use MSAA in GPU rasterization if Skia suggests it

cc/resources/resource_provider.h

Index: cc/resources/resource_provider.h
diff --git a/cc/resources/resource_provider.h b/cc/resources/resource_provider.h
index 73b5a23dcdf3c249f075946ce7a0c6deb77ac0d6..243c21f8912c5db62b42bfbaa7b1fe9baedc5b2a 100644
--- a/cc/resources/resource_provider.h
+++ b/cc/resources/resource_provider.h
@@ -90,6 +90,10 @@ class CC_EXPORT ResourceProvider {
   ResourceFormat best_texture_format() const { return best_texture_format_; }
   size_t num_resources() const { return resources_.size(); }
 
+  unsigned num_gpu_rasterization_samples() const {
+    return num_gpu_rasterization_samples_;
+  }
+
   // Checks whether a resource is in use by a consumer.
   bool InUseByConsumer(ResourceId id);
 
@@ -635,7 +639,7 @@ class CC_EXPORT ResourceProvider {
   scoped_ptr<TextureUploader> texture_uploader_;
   int max_texture_size_;
   ResourceFormat best_texture_format_;
-
+  unsigned num_gpu_rasterization_samples_;
   base::ThreadChecker thread_checker_;
 
   scoped_refptr<Fence> current_read_lock_fence_;