Allow Blink to generate cc::FrameSinkId from RenderThread

third_party/WebKit/public/platform/Platform.h

Index: third_party/WebKit/public/platform/Platform.h
diff --git a/third_party/WebKit/public/platform/Platform.h b/third_party/WebKit/public/platform/Platform.h
index 747885a940b479fac6bcd5a2f069c40775d78f50..5285ad95ca43c120b0be8d7854a2098f084834f4 100644
--- a/third_party/WebKit/public/platform/Platform.h
+++ b/third_party/WebKit/public/platform/Platform.h
@@ -321,6 +321,14 @@ class BLINK_PLATFORM_EXPORT Platform {
   // the process's process ID.
   virtual uint32_t getUniqueIdForProcess() { return 0; }
 
+  // Render Thread -------------------------------------------------------
+
+  // Returns a unique client ID for the process of the current render thread
+  virtual uint32_t getClientId() { return 0; }

[Fady Samuel, 2016/11/22 23:41:18]

How about just exposing a "generateFrameSinkId" which is what you really need?

[xlai (Olivia), 2016/11/22 23:51:55]

I would rather keep an interface function as straightforward as possible. 

Another reason, I'm wondering can we directly use cc::FrameSinkId here? WDYT,
kinoku@?

[kinuko, 2016/11/23 10:33:30]

(Putting aside the discussion if it's recommended or not) yes it's possible, a
few public headers actually include cc headers and refer cc types.

+  // Generates a new routing ID. This method normally gets delegated to a
+  // MessageRouter.
+  virtual int generateRoutingId() { return 0; }

[kinuko, 2016/11/23 10:33:30]

Is the 'routing ID' about IPC routing or render thread specific term?  'routing
ID' is not the concept blink usually understands, do we really need this
interface here?

+
   // Message Ports -------------------------------------------------------
 
   // Creates a Message Port Channel pair. This can be called on any thread.