Some touch-event forwarding optimization.

content/common/view_messages.h

 // Copyright (c) 2012 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 page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "content/common/content_export.h"
@@ skipping 1571 matching lines @@
 
 // Notifies that the pinned-to-side state of the content changed.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_DidChangeScrollbarsForMainFrame,
                     bool /* pinned_to_left */,
                     bool /* pinned_to_right */)
 
 // Notifies that the number of JavaScript scroll handlers changed.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_DidChangeNumWheelEvents,
                     int /* count */)
 
+// Notifies that the number of JavaScript touch event handlers changed.
+IPC_MESSAGE_ROUTED1(ViewHostMsg_DidChangeNumTouchEvents,
+                    int /* count */)
+
 // A message from HTML-based UI.  When (trusted) Javascript calls
 // send(message, args), this message is sent to the browser.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_WebUISend,
                     GURL /* source_url */,
                     std::string  /* message */,
                     base::ListValue /* args */)
 
 // A renderer sends this to the browser process when it wants to
 // create a ppapi plugin.  The browser will create the plugin process if
 // necessary, and will return a handle to the channel on success.
@@ skipping 334 matching lines @@
 // have a javascript send a native value (string, number, boolean) to the
 // listener in Cpp. (DomAutomationController)
 IPC_MESSAGE_ROUTED2(ViewHostMsg_DomOperationResponse,
                     std::string  /* json_string */,
                     int  /* automation_id */)
 
 // Enable or disable inverting of web content pixels, for users who prefer
 // white-on-black.
 IPC_MESSAGE_ROUTED1(ViewMsg_InvertWebContent,
                     bool /* invert */)