base: Stop passing a non-const ref to ObserverListBase::Iterator.

ui/events/platform/platform_event_source.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/events/platform/platform_event_source.h"
 
 #include <algorithm>
 
 #include "base/message_loop/message_loop.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
@@ skipping 58 matching lines @@
   uint32_t action = POST_DISPATCH_PERFORM_DEFAULT;
 
   FOR_EACH_OBSERVER(PlatformEventObserver, observers_,
                     WillProcessEvent(platform_event));
   // Give the overridden dispatcher a chance to dispatch the event first.
   if (overridden_dispatcher_)
     action = overridden_dispatcher_->DispatchEvent(platform_event);
 
   if ((action & POST_DISPATCH_PERFORM_DEFAULT) &&
       dispatchers_.might_have_observers()) {
-    ObserverList<PlatformEventDispatcher>::Iterator iter(dispatchers_);
+    ObserverList<PlatformEventDispatcher>::Iterator iter(&dispatchers_);
     while (PlatformEventDispatcher* dispatcher = iter.GetNext()) {
       if (dispatcher->CanDispatchEvent(platform_event))
         action = dispatcher->DispatchEvent(platform_event);
       if (action & POST_DISPATCH_STOP_PROPAGATION)
         break;
     }
   }
   FOR_EACH_OBSERVER(PlatformEventObserver, observers_,
                     DidProcessEvent(platform_event));
 
@@ skipping 12 matching lines @@
 
 void PlatformEventSource::OnDispatcherListChanged() {
 }
 
 void PlatformEventSource::OnOverriddenDispatcherRestored() {
   CHECK(overridden_dispatcher_);
   overridden_dispatcher_restored_ = true;
 }
 
 }  // namespace ui