aura: Remove client::UserActionClient.

chrome/browser/ui/views/frame/desktop_user_action_handler_aura.cc

-// Copyright (c) 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 "chrome/browser/ui/views/frame/desktop_user_action_handler_aura.h"
-
-#include "chrome/browser/ui/browser.h"
-#include "chrome/browser/ui/tabs/tab_strip_model.h"
-#include "content/public/browser/web_contents.h"
-
-DesktopUserActionHandlerAura::DesktopUserActionHandlerAura(Browser* browser)
-    : browser_(browser) {
-}
-
-DesktopUserActionHandlerAura::~DesktopUserActionHandlerAura() {}
-
-bool DesktopUserActionHandlerAura::OnUserAction(
-    aura::client::UserActionClient::Command command) {
-  switch (command) {
-    case aura::client::UserActionClient::BACK: {
-      content::WebContents* contents = GetActiveWebContents();
-      if (contents && contents->GetController().CanGoBack()) {
-        contents->GetController().GoBack();
-        return true;
-      }
-      break;
-    }
-    case aura::client::UserActionClient::FORWARD: {
-      content::WebContents* contents = GetActiveWebContents();
-      if (contents && contents->GetController().CanGoForward()) {
-        contents->GetController().GoForward();
-        return true;
-      }
-      break;
-    }
-    default:
-      break;
-  }
-  return false;
-}
-
-content::WebContents*
-DesktopUserActionHandlerAura::GetActiveWebContents() const {
-  return browser_->tab_strip_model()->GetActiveWebContents();
-}