Fix a mouse lock problem on Windows where in clicks outside the web page would also cause mouse loc…

content/browser/renderer_host/render_widget_host_view_aura.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 "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include <set>
 
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
@@ skipping 1504 matching lines @@
 
 void RenderWidgetHostViewAura::UnlockMouse() {
   tooltip_disabler_.reset();
 
   aura::Window* root_window = window_->GetRootWindow();
   if (!mouse_locked_ || !root_window)
     return;
 
   mouse_locked_ = false;
 
-#if !defined(OS_WIN)
-  window_->ReleaseCapture();
-#else
+  if (window_->HasCapture())
+    window_->ReleaseCapture();
+
+#if defined(OS_WIN)
   ::ClipCursor(NULL);
 #endif
+
   window_->MoveCursorTo(unlocked_mouse_position_);
   aura::client::CursorClient* cursor_client =
       aura::client::GetCursorClient(root_window);
   if (cursor_client) {
     cursor_client->UnlockCursor();
     cursor_client->ShowCursor();
   }
 
   host_->LostMouseLock();
 }
@@ skipping 1297 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewBase, public:
 
 // static
 void RenderWidgetHostViewBase::GetDefaultScreenInfo(WebScreenInfo* results) {
   GetScreenInfoForWindow(results, NULL);
 }
 
 }  // namespace content