Makes PlatformEventSource creation in Env conditional

ui/aura/env.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 "ui/aura/env.h"
 
 #include "ui/aura/env_observer.h"
 #include "ui/aura/input_state_lookup.h"
 #include "ui/compositor/compositor.h"
 #include "ui/events/event_target_iterator.h"
@@ skipping 13 matching lines @@
       input_state_lookup_(InputStateLookup::Create().Pass()) {
 }
 
 Env::~Env() {
   FOR_EACH_OBSERVER(EnvObserver, observers_, OnWillDestroyEnv());
 
   ui::Compositor::Terminate();
 }
 
 //static
-void Env::CreateInstance() {
+void Env::CreateInstance(bool create_event_source) {
   if (!instance_) {
     instance_ = new Env;
-    instance_->Init();
+    instance_->Init(create_event_source);
   }
 }
 
 // static
 Env* Env::GetInstance() {
   DCHECK(instance_) << "Env::CreateInstance must be called before getting "
                        "the instance of Env.";
   return instance_;
 }
 
@@ skipping 12 matching lines @@
 }
 
 bool Env::IsMouseButtonDown() const {
   return input_state_lookup_.get() ? input_state_lookup_->IsMouseButtonDown() :
       mouse_button_flags_ != 0;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // Env, private:
 
-void Env::Init() {
+void Env::Init(bool create_event_source) {
   ui::Compositor::Initialize();
 
-  if (!ui::PlatformEventSource::GetInstance())
+  if (create_event_source && !ui::PlatformEventSource::GetInstance())
     event_source_ = ui::PlatformEventSource::CreateDefault();
 }
 
 void Env::NotifyWindowInitialized(Window* window) {
   FOR_EACH_OBSERVER(EnvObserver, observers_, OnWindowInitialized(window));
 }
 
 void Env::NotifyHostInitialized(WindowTreeHost* host) {
   FOR_EACH_OBSERVER(EnvObserver, observers_, OnHostInitialized(host));
 }
@@ skipping 16 matching lines @@
 scoped_ptr<ui::EventTargetIterator> Env::GetChildIterator() const {
   return scoped_ptr<ui::EventTargetIterator>();
 }
 
 ui::EventTargeter* Env::GetEventTargeter() {
   NOTREACHED();
   return NULL;
 }
 
 }  // namespace aura