Implement asynchronous interface/plumbing for GetDefaultPrintSettings.

ppapi/proxy/ppb_instance_proxy.h

Index: ppapi/proxy/ppb_instance_proxy.h
diff --git a/ppapi/proxy/ppb_instance_proxy.h b/ppapi/proxy/ppb_instance_proxy.h
index e2ac4d7d1f147fd3db915622e987d118d87ad61b..b4adb3b21469ca9f4ebc6b965e5fc53f44c535af 100644
--- a/ppapi/proxy/ppb_instance_proxy.h
+++ b/ppapi/proxy/ppb_instance_proxy.h
@@ -87,9 +87,10 @@ class PPB_Instance_Proxy : public InterfaceProxy,
   virtual int32_t LockMouse(PP_Instance instance,
                             scoped_refptr<TrackedCallback> callback) OVERRIDE;
   virtual void UnlockMouse(PP_Instance instance) OVERRIDE;
-  virtual PP_Bool GetDefaultPrintSettings(
+  virtual int32_t GetDefaultPrintSettings(
       PP_Instance instance,
-      PP_PrintSettings_Dev* print_settings) OVERRIDE;
+      PP_PrintSettings_Dev* print_settings,
+      scoped_refptr<TrackedCallback> callback) OVERRIDE;
   virtual void SetTextInputType(PP_Instance instance,
                                 PP_TextInput_Type type) OVERRIDE;
   virtual void UpdateCaretPosition(PP_Instance instance,
@@ -156,9 +157,6 @@ class PPB_Instance_Proxy : public InterfaceProxy,
                             SerializedVarReceiveInput message);
   void OnHostMsgLockMouse(PP_Instance instance);
   void OnHostMsgUnlockMouse(PP_Instance instance);
-  void OnHostMsgGetDefaultPrintSettings(PP_Instance instance,
-                                        PP_PrintSettings_Dev* settings,
-                                        bool* result);
   void OnHostMsgSetCursor(PP_Instance instance,
                           int32_t type,
                           const ppapi::HostResource& custom_image,
@@ -194,6 +192,12 @@ class PPB_Instance_Proxy : public InterfaceProxy,
 
   void MouseLockCompleteInHost(int32_t result, PP_Instance instance);
 
+  void OnPluginMsgGetDefaultPrintSettingsComplete(
+      int32 routing_id,
+      PP_Instance,
+      const PP_PrintSettings_Dev& settings,
+      int32_t result);
+
   ProxyCompletionCallbackFactory<PPB_Instance_Proxy> callback_factory_;
 };