Implement native bindings for cast extensions API

chrome/renderer/extensions/webrtc_native_handler.h

Index: chrome/renderer/extensions/webrtc_native_handler.h
diff --git a/chrome/renderer/extensions/webrtc_native_handler.h b/chrome/renderer/extensions/webrtc_native_handler.h
index fb3ecdcccf9d449b31e6d8b8deb79180aafbac4d..bcaf98dd264161a8aaa42f3711505e07780efa30 100644
--- a/chrome/renderer/extensions/webrtc_native_handler.h
+++ b/chrome/renderer/extensions/webrtc_native_handler.h
@@ -5,9 +5,15 @@
 #ifndef CHROME_RENDERER_EXTENSIONS_WEBRTC_NATIVE_HANDLER_H_
 #define CHROME_RENDERER_EXTENSIONS_WEBRTC_NATIVE_HANDLER_H_
 
+#include <map>
+
+#include "base/memory/linked_ptr.h"
 #include "chrome/renderer/extensions/object_backed_native_handler.h"
 #include "v8/include/v8.h"
 
+class CastSendTransport;
+class CastUdpTransport;
+
 namespace extensions {
 
 class ChromeV8Context;
@@ -41,6 +47,18 @@ class WebRtcNativeHandler : public ObjectBackedNativeHandler {
   void StopCastUdpTransport(
       const v8::FunctionCallbackInfo<v8::Value>& args);
 
+  // Helper methods to get transport indexed by |transport_id|.
+  // If the transport is not found then return NULL and throw a v8

[scherkus (not reviewing), 2013/10/29 17:38:17]

as much as it's nice to save a handful of lines of code, I'm not too hot having
helpers (marked as const, even!) modify V8 state by throwing an exception

when I was reading the code it looked strange returning from
Get{Send/Udp}Transport() calls w/o doing anything

I'd almost prefer the extra bit of V8::ThrowException() code for clarity or at
least the very least renaming these to Get{Udp,Send}TransportOrThrowException().

WDYT?

[Alpha Left Google, 2013/10/29 19:52:18]

Okay I'll move the exception to each caller.

+  // exception.
+  CastSendTransport* GetSendTransport(int transport_id) const;
+  CastUdpTransport* GetUdpTransport(int transport_id) const;
+
+  int last_transport_id_;

[justinlin, 2013/10/29 18:22:29]

You probably want to take a look at ApiResourceManager:
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ext...

It's what's commonly used in extension API's to create objects that are keyed by
some id passed back to js clients (socket api's can serve as inspiration).

[Alpha Left Google, 2013/10/29 19:52:18]

I don't think that's doable because ApiResourceManager is used in the browser
process specifically.

+  typedef std::map<int, linked_ptr<CastSendTransport> > SendTransportMap;
+  SendTransportMap send_transport_map_;
+  typedef std::map<int, linked_ptr<CastUdpTransport> > UdpTransportMap;
+  UdpTransportMap udp_transport_map_;
+
   DISALLOW_COPY_AND_ASSIGN(WebRtcNativeHandler);
 };