[Merge] Make mouse buttons 8 - 11 navigate forward and back in history

ui/aura/window_event_dispatcher.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 "ui/aura/window_event_dispatcher.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 760 matching lines @@
     } else {
       // We may have a held event for a period between the time move_hold_count_
       // fell to 0 and the DispatchHeldEvents executes. Since we're going to
       // dispatch the new event directly below, we can reset the old one.
       held_move_event_.reset();
     }
   }
 
   const int kMouseButtonFlagMask = ui::EF_LEFT_MOUSE_BUTTON |
                                    ui::EF_MIDDLE_MOUSE_BUTTON |
-                                   ui::EF_RIGHT_MOUSE_BUTTON;
+                                   ui::EF_RIGHT_MOUSE_BUTTON |
+                                   ui::EF_BACK_MOUSE_BUTTON |
+                                   ui::EF_FORWARD_MOUSE_BUTTON;
   switch (event->type()) {
     case ui::ET_MOUSE_EXITED:
       if (!target || target == window()) {
         DispatchDetails details =
             DispatchMouseEnterOrExit(target, *event, ui::ET_MOUSE_EXITED);
         if (details.dispatcher_destroyed) {
           event->SetHandled();
           return;
         }
         mouse_moved_handler_ = NULL;
@@ skipping 99 matching lines @@
   }
 
   // This flag is set depending on the gestures recognized in the call above,
   // and needs to propagate with the forwarded event.
   event->set_may_cause_scrolling(orig_event.may_cause_scrolling());
 
   PreDispatchLocatedEvent(target, event);
 }
 
 }  // namespace aura