Pepper: Move DoPostMessage out of trusted plugin.

ppapi/native_client/src/trusted/plugin/service_runtime.h

Index: ppapi/native_client/src/trusted/plugin/service_runtime.h
diff --git a/ppapi/native_client/src/trusted/plugin/service_runtime.h b/ppapi/native_client/src/trusted/plugin/service_runtime.h
index 74dc68d633311faaf9cab66ebdc83ade66a3fbf3..2c1e9a58610c82588ebe98387a3ebbd886d45fe9 100644
--- a/ppapi/native_client/src/trusted/plugin/service_runtime.h
+++ b/ppapi/native_client/src/trusted/plugin/service_runtime.h
@@ -76,13 +76,6 @@ struct SelLdrStartParams {
 };
 
 // Callback resources are essentially our continuation state.
-struct PostMessageResource {
- public:
-  explicit PostMessageResource(std::string msg)
-      : message(msg) {}
-  std::string message;
-};
-
 struct OpenManifestEntryResource {
  public:
   OpenManifestEntryResource(const std::string& target_url,
@@ -186,9 +179,6 @@ class PluginReverseInterface: public nacl::ReverseInterface {
                               OpenManifestEntryAsyncCallback* callback);
 
  protected:
-  virtual void PostMessage_MainThreadContinuation(PostMessageResource* p,
-                                                  int32_t err);
-
   virtual void OpenManifestEntry_MainThreadContinuation(
       OpenManifestEntryResource* p,
       int32_t err);