Added the Vulkan Context Provider implementation.

cc/output/output_surface.h

Index: cc/output/output_surface.h
diff --git a/cc/output/output_surface.h b/cc/output/output_surface.h
index da4b647bdbb81e0f54fc54e2b83e91dd698b026f..7da4cc0af8904ab36a2082db2fddd910e502feec 100644
--- a/cc/output/output_surface.h
+++ b/cc/output/output_surface.h
@@ -60,7 +60,8 @@ class CC_EXPORT OutputSurface : public base::trace_event::MemoryDumpProvider {
   explicit OutputSurface(scoped_refptr<ContextProvider> context_provider);
 #if defined(ENABLE_VULKAN)
   explicit OutputSurface(
-      scoped_refptr<VulkanContextProvider> vulkan_context_provider);
+      scoped_refptr<VulkanContextProvider> vulkan_context_provider,
+      bool use_vulkan);

[piman, 2016/04/19 01:36:42]

What's the reason for use_vulkan, it's not used except for a DCHECK?

[David Yen, 2016/04/19 22:20:27]

This was so I could override the constructor, it conflicts with the
OutputSurface(ContextProvider) constructor because it is the base class.

Perhaps a better way is to just call the constructor with all the arguments and
pass in nullptr for the other arguments.

[piman, 2016/04/19 23:29:57]

I think you're running into a scoped_refptr limitation, should be fixed with
https://codereview.chromium.org/1904603002/

 #endif
   explicit OutputSurface(std::unique_ptr<SoftwareOutputDevice> software_device);