Adding UMA for sync IPCs

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 2023 matching lines @@
 
 // Puts the browser into "tab fullscreen" mode for the sending renderer.
 // See the comment in chrome/browser/ui/browser.h for more details.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_ToggleFullscreen,
                     bool /* enter_fullscreen */)
 
 // Send back a string to be recorded by UserMetrics.
 IPC_MESSAGE_CONTROL1(ViewHostMsg_UserMetricsRecordAction,
                      std::string /* action */)
 
+// Send back the elapsed time for sync IPC to be recorded by histogram.
+IPC_MESSAGE_CONTROL1(ViewHostMsg_SyncIPCElapsedTime,
+                     base::TimeDelta /* millisecons */)
+
 // Notifies the browser that the page was or was not saved as MHTML.
 IPC_MESSAGE_CONTROL2(ViewHostMsg_SavedPageAsMHTML,
                      int /* job_id */,
                      int64 /* size of the MHTML file, -1 if error */)
 
 IPC_MESSAGE_ROUTED3(ViewHostMsg_SendCurrentPageAllSavableResourceLinks,
                     std::vector<GURL> /* all savable resource links */,
                     std::vector<content::Referrer> /* all referrers */,
                     std::vector<GURL> /* all frame links */)
 
@@ skipping 30 matching lines @@
 // (according to the value of is_hung). The browser can give the user the
 // option of killing the plugin.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_PepperPluginHung,
                     int /* plugin_child_id */,
                     FilePath /* path */,
                     bool /* is_hung */)
 
 // Screen was rotated. Dispatched to the onorientationchange javascript API.
 IPC_MESSAGE_ROUTED1(ViewMsg_OrientationChangeEvent,
                     int /* orientation */)