Add Keyboard Latency UMA Metrics.

chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/auto_reset.h"
 #include "base/mac/bundle_locations.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/app/vector_icons/vector_icons.h"
@@ skipping 285 matching lines @@
       return NO;
 
     // Forward the event to the renderer.
     // TODO(rohitrao): Should this call -[BaseView keyEvent:]?  Is there code in
     // that function that we want to keep or avoid? Calling
     // |ForwardKeyboardEvent()| directly ignores edit commands, which breaks
     // cmd-up/down if we ever decide to include |moveToBeginningOfDocument:| in
     // the list above.
     content::RenderViewHost* render_view_host =
         web_contents->GetRenderViewHost();
+
+    // TODO(tdresser): get the hardware timestamp from the NSEvent.
     render_view_host->GetWidget()->ForwardKeyboardEvent(
         NativeWebKeyboardEvent(event));
     return YES;
   }
 
   return NO;
 }
 
 // Methods from FindBar
 - (void)showFindBar:(BOOL)animate {
@@ skipping 345 matching lines @@
 }
 
 - (BrowserWindowController*)browserWindowController {
   if (!browser_)
     return nil;
   return [BrowserWindowController
       browserWindowControllerForWindow:browser_->window()->GetNativeWindow()];
 }
 
 @end