clang/win: Let some chromium_code targets build with -Wextra.

media/base/user_input_monitor_win.cc

 // Copyright 2013 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 "media/base/user_input_monitor.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 162 matching lines @@
   }
 }
 
 LRESULT UserInputMonitorWinCore::OnInput(HRAWINPUT input_handle) {
   DCHECK(ui_task_runner_->BelongsToCurrentThread());
 
   // Get the size of the input record.
   UINT size = 0;
   UINT result = GetRawInputData(
       input_handle, RID_INPUT, NULL, &size, sizeof(RAWINPUTHEADER));
-  if (result == -1) {
+  if (result == static_cast<UINT>(-1)) {
     PLOG(ERROR) << "GetRawInputData() failed";
     return 0;
   }
   DCHECK_EQ(0u, result);
 
   // Retrieve the input record itself.
   scoped_ptr<uint8[]> buffer(new uint8[size]);
   RAWINPUT* input = reinterpret_cast<RAWINPUT*>(buffer.get());
   result = GetRawInputData(
       input_handle, RID_INPUT, buffer.get(), &size, sizeof(RAWINPUTHEADER));
-  if (result == -1) {
+  if (result == static_cast<UINT>(-1)) {
     PLOG(ERROR) << "GetRawInputData() failed";
     return 0;
   }
   DCHECK_EQ(size, result);
 
   // Notify the observer about events generated locally.
   if (input->header.dwType == RIM_TYPEMOUSE && input->header.hDevice != NULL) {
     POINT position;
     if (!GetCursorPos(&position)) {
       position.x = 0;
@@ skipping 103 matching lines @@
 
 }  // namespace
 
 scoped_ptr<UserInputMonitor> UserInputMonitor::Create(
     const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner) {
   return scoped_ptr<UserInputMonitor>(new UserInputMonitorWin(ui_task_runner));
 }
 
 }  // namespace media