Revert 255385 "aura: Remove client::UserActionClient."

trunk/src/chrome/browser/ui/views/frame/browser_command_handler_x11.cc

-// Copyright 2014 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/browser_command_handler_x11.h"
-
-#include <X11/Xlib.h>
-
-#include "chrome/browser/ui/browser.h"
-#include "chrome/browser/ui/tabs/tab_strip_model.h"
-#include "content/public/browser/navigation_controller.h"
-#include "content/public/browser/web_contents.h"
-#include "ui/events/event.h"
-#include "ui/events/event_utils.h"
-
-BrowserCommandHandlerX11::BrowserCommandHandlerX11(Browser* browser)
-    : browser_(browser) {}
-
-BrowserCommandHandlerX11::~BrowserCommandHandlerX11() {}
-
-void BrowserCommandHandlerX11::OnMouseEvent(ui::MouseEvent* event) {
-  if (event->type() != ui::ET_MOUSE_PRESSED)
-    return;
-  XEvent* xevent = event->native_event();
-  if (!xevent)
-    return;
-  int button = xevent->type == GenericEvent ? ui::EventButtonFromNative(xevent)
-                                            : xevent->xbutton.button;
-
-  // Standard Linux mouse buttons for going back and forward.
-  const int kBackMouseButton = 8;
-  const int kForwardMouseButton = 9;
-  if (button == kBackMouseButton || button == kForwardMouseButton) {
-    content::WebContents* contents =
-        browser_->tab_strip_model()->GetActiveWebContents();
-    if (!contents)
-      return;
-    content::NavigationController& controller = contents->GetController();
-    if (button == kBackMouseButton && controller.CanGoBack())
-      controller.GoBack();
-    else if (button == kForwardMouseButton && controller.CanGoForward())
-      controller.GoForward();
-    // Always consume the event, whether a navigation was successful or not.
-    event->SetHandled();
-  }
-}