Remove keep-alive impulse IPCs from NaCl modules.

ppapi/shared_impl/ppapi_globals.h

Index: ppapi/shared_impl/ppapi_globals.h
diff --git a/ppapi/shared_impl/ppapi_globals.h b/ppapi/shared_impl/ppapi_globals.h
index f069ab065926e38ded530ca3aa7c6a17d9e413e6..3dcc901fa773922d8b8a00d825b228ac13b75396 100644
--- a/ppapi/shared_impl/ppapi_globals.h
+++ b/ppapi/shared_impl/ppapi_globals.h
@@ -128,12 +128,6 @@ class PPAPI_SHARED_EXPORT PpapiGlobals {
   virtual bool IsHostGlobals() const;
   virtual bool IsPluginGlobals() const;
 
-  // Records that the plugin is active. The plugin reports that it is active to
-  // containers that monitor and shutdown idle content such as background apps.
-  // This method only has an effect on the plugin process, calls from the
-  // renderer process will have no effect.
-  virtual void MarkPluginIsActive();
-
  private:
   // Return the thread-local pointer which is used only for unit testing. It
   // should always be NULL when running in production. It allows separate