Extensions: Send the tab id to platform apps.

chrome/renderer/extensions/dispatcher.h

Index: chrome/renderer/extensions/dispatcher.h
===================================================================
--- chrome/renderer/extensions/dispatcher.h	(revision 248111)
+++ chrome/renderer/extensions/dispatcher.h	(working copy)
@@ -143,6 +143,8 @@
       const base::ListValue& args,
       bool user_gesture);
 
+  void ClearPortData(int port_id);
+
  private:
   friend class ::ChromeRenderViewTest;
   FRIEND_TEST_ALL_PREFIXES(RendererPermissionsPolicyDelegateTest,
@@ -309,6 +311,9 @@
   std::string system_font_family_;
   std::string system_font_size_;
 
+  // Mapping of port IDs to tabs. If there is no tab, the value would be -1.
+  std::map<int, int> port_to_tab_id_map_;
+
   DISALLOW_COPY_AND_ASSIGN(Dispatcher);
 };