Use macros to define pepper interfaces

ppapi/proxy/ppb_video_decoder_proxy.h

Index: ppapi/proxy/ppb_video_decoder_proxy.h
diff --git a/ppapi/proxy/ppb_video_decoder_proxy.h b/ppapi/proxy/ppb_video_decoder_proxy.h
index b34cb2257be11ad52c22848234c6dcf040f0091e..32d1ec67d48705f10fbde8cc4441a91230b4d2e8 100644
--- a/ppapi/proxy/ppb_video_decoder_proxy.h
+++ b/ppapi/proxy/ppb_video_decoder_proxy.h
@@ -17,11 +17,9 @@ namespace proxy {
 
 class PPB_VideoDecoder_Proxy : public InterfaceProxy {
  public:
-  PPB_VideoDecoder_Proxy(Dispatcher* dispatcher, const void* target_interface);
+  PPB_VideoDecoder_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_VideoDecoder_Proxy();
 
-  static const Info* GetInfo();
-
   // Creates a VideoDecoder object in the plugin process.
   static PP_Resource CreateProxyResource(
       PP_Instance instance,
@@ -31,9 +29,7 @@ class PPB_VideoDecoder_Proxy : public InterfaceProxy {
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
-  const PPB_VideoDecoder_Dev* ppb_video_decoder_target() const {
-    return static_cast<const PPB_VideoDecoder_Dev*>(target_interface());
-  }
+  static const InterfaceID kInterfaceID = INTERFACE_ID_PPB_VIDEO_DECODER_DEV;
 
  private:
   // Message handlers in the renderer process to receive messages from the