Further instrumentations to find jank in Windows message processing.

ui/gfx/win/hwnd_util.cc

 // 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.
 
 #include "ui/gfx/win/hwnd_util.h"
 
 #include "base/i18n/rtl.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_util.h"
 #include "base/tracked_objects.h"
 #include "base/win/metro.h"
 #include "base/win/win_util.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace gfx {
 
@@ skipping 87 matching lines @@
   return oldwindow_proc;
 }
 
 void* SetWindowUserData(HWND hwnd, void* user_data) {
   return
       reinterpret_cast<void*>(SetWindowLongPtr(hwnd, GWLP_USERDATA,
           reinterpret_cast<LONG_PTR>(user_data)));
 }
 
 void* GetWindowUserData(HWND hwnd) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/440919 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION("440919 GetWindowUserData"));
+
   DWORD process_id = 0;
   GetWindowThreadProcessId(hwnd, &process_id);
   // A window outside the current process needs to be ignored.
   if (process_id != ::GetCurrentProcessId())
     return NULL;

[cpu_(ooo_6.6-7.5), 2015/01/06 20:46:13]

It would be very surprising if this is a bottleneck. I am betting is not.

   return reinterpret_cast<void*>(GetWindowLongPtr(hwnd, GWLP_USERDATA));
 }
 
 #pragma warning(pop)
 
 bool DoesWindowBelongToActiveWindow(HWND window) {
   DCHECK(window);
   HWND top_window = ::GetAncestor(window, GA_ROOT);
   if (!top_window)
     return false;
@@ skipping 114 matching lines @@
   HMODULE metro = base::win::GetMetroModule();
   if (!metro)
     return get_real_hwnd ? ::GetDesktopWindow() : HWND_DESKTOP;
   // In windows 8 metro-mode the root window is not the desktop.
   RootWindow root_window =
       reinterpret_cast<RootWindow>(::GetProcAddress(metro, "GetRootWindow"));
   return root_window();
 }
 
 }  // namespace gfx