Input latency performance test that uses tracing.

content/browser/renderer_host/render_widget_host.cc

 // Copyright (c) 2011 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.
 
 #include "content/browser/renderer_host/render_widget_host.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 1018 matching lines @@
 
     // If gpu process does painting, scroll_rect and copy_rects are always empty
     // and backing store is never used.
     if (dib) {
       if (dib->size() < size) {
         DLOG(WARNING) << "Transport DIB too small for given rectangle";
         content::RecordAction(
             UserMetricsAction("BadMessageTerminate_RWH1"));
         process()->ReceivedBadMessage();
       } else {
+        UNSHIPPED_TRACE_EVENT_INSTANT2("test_latency", "UpdateRect",
+            "x+y", params.bitmap_rect.x() + params.bitmap_rect.y(),
+            "color", 0xffffff & *static_cast<uint32*>(dib->memory()));
+        UNSHIPPED_TRACE_EVENT_INSTANT1("test_latency", "UpdateRectWidth",
+            "width", params.bitmap_rect.width());
+
         // Scroll the backing store.
         if (!params.scroll_rect.IsEmpty()) {
           ScrollBackingStoreRect(params.dx, params.dy,
                                  params.scroll_rect,
                                  params.view_size);
         }
 
         // Paint the backing store. This will update it with the
         // renderer-supplied bits. The view will read out of the backing store
         // later to actually draw to the screen.
@@ skipping 482 matching lines @@
     ui_shim->Send(new AcceleratedSurfaceMsg_BuffersSwappedACK(route_id));
 }
 
 // static
 void RenderWidgetHost::AcknowledgePostSubBuffer(int32 route_id,
                                                 int gpu_host_id) {
   GpuProcessHostUIShim* ui_shim = GpuProcessHostUIShim::FromID(gpu_host_id);
   if (ui_shim)
     ui_shim->Send(new AcceleratedSurfaceMsg_PostSubBufferACK(route_id));
 }