[Extensions] Remove the source_tab_id property on API request messages

extensions/common/extension_messages.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // IPC messages for extensions.
 // Multiply-included message file, hence no include guard.
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 82 matching lines @@
   // where we expose APIs to normal web pages using the extension function
   // system.
   IPC_STRUCT_MEMBER(std::string, extension_id)
 
   // URL of the frame the request was sent from. This isn't necessarily an
   // extension url. Extension requests can also originate from content scripts,
   // in which case extension_id will indicate the ID of the associated
   // extension. Or, they can originate from hosted apps or normal web pages.
   IPC_STRUCT_MEMBER(GURL, source_url)
 
-  // The id of the tab that sent this request, or -1 if there is no source tab.
-  IPC_STRUCT_MEMBER(int, source_tab_id)
-
   // Unique request id to match requests and responses.
   IPC_STRUCT_MEMBER(int, request_id)
 
   // True if request has a callback specified.
   IPC_STRUCT_MEMBER(bool, has_callback)
 
   // True if request is executed in response to an explicit user gesture.
   IPC_STRUCT_MEMBER(bool, user_gesture)
 
   // If this API call is for a service worker, then this is the worker thread
@@ skipping 810 matching lines @@
                      int64_t /* service_worker_version_id */,
                      std::string /* request_uuid */)
 
 // Asks the browser to decrement the pending activity count for
 // the worker with version id |service_worker_version_id|.
 // |request_uuid| must match the GUID of a previous request, otherwise the
 // browser process ignores the IPC.
 IPC_MESSAGE_CONTROL2(ExtensionHostMsg_DecrementServiceWorkerActivity,
                      int64_t /* service_worker_version_id */,
                      std::string /* request_uuid */)