extensions: Extract the dependency on browser_view from extension_input_api.cc.

chrome/browser/ui/views/top_level_widget_views.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 "chrome/browser/ui/top_level_widget.h"
+
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/views/frame/browser_view.h"
+#include "ui/views/widget/widget.h"
+
+namespace chrome {
+
+views::Widget* GetTopLevelWidgetForBrowser(Browser* browser) {
+  if (!browser)
+    return NULL;
+
+  BrowserWindow* window = browser->window();
+  if (!window)
+    return NULL;
+
+  BrowserView* browser_view = BrowserView::GetBrowserViewForBrowser(browser);
+  return browser_view ? browser_view->GetWidget() : NULL;
+}
+
+}  // namespace chrome