Use macros to define pepper interfaces

ppapi/proxy/ppb_flash_proxy.h

Index: ppapi/proxy/ppb_flash_proxy.h
diff --git a/ppapi/proxy/ppb_flash_proxy.h b/ppapi/proxy/ppb_flash_proxy.h
index f893ce2b3b6d895b28ad95d4977a4d1dd9ecf1d4..8bb15eb554f7ebba12764bc983b61629c83418df 100644
--- a/ppapi/proxy/ppb_flash_proxy.h
+++ b/ppapi/proxy/ppb_flash_proxy.h
@@ -29,15 +29,11 @@ class SerializedVarReturnValue;
 
 class PPB_Flash_Proxy : public InterfaceProxy {
  public:
-  PPB_Flash_Proxy(Dispatcher* dispatcher, const void* target_interface);
+  PPB_Flash_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_Flash_Proxy();
 
   static const Info* GetInfo();
 
-  const PPB_Flash* ppb_flash_target() const {
-    return static_cast<const PPB_Flash*>(target_interface());
-  }
-
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
@@ -59,6 +55,13 @@ class PPB_Flash_Proxy : public InterfaceProxy {
   void OnMsgQuitMessageLoop(PP_Instance instance);
   void OnMsgGetLocalTimeZoneOffset(PP_Instance instance, PP_Time t,
                                    double* result);
+
+  // When this proxy is in the host side, this value caches the interface
+  // pointer so we don't have to retrieve it from the dispatcher each time.
+  // In the plugin, this value is always NULL.
+  const PPB_Flash* ppb_flash_impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(PPB_Flash_Proxy);
 };
 
 }  // namespace proxy