Relanding the EventTarget fixes for Aura (Ash) as the previous attempt was reverted due to interact…

ash/shell.cc

Index: ash/shell.cc
===================================================================
--- ash/shell.cc	(revision 164745)
+++ ash/shell.cc	(working copy)
@@ -510,11 +510,11 @@
 }
 
 void Shell::AddEnvEventFilter(aura::EventFilter* filter) {
-  aura::Env::GetInstance()->AddPreTargetHandler(filter);
+  AddPreTargetHandler(filter);
 }
 
 void Shell::RemoveEnvEventFilter(aura::EventFilter* filter) {
-  aura::Env::GetInstance()->RemovePreTargetHandler(filter);
+  RemovePreTargetHandler(filter);
 }
 
 void Shell::ShowContextMenu(const gfx::Point& location_in_screen) {
@@ -733,6 +733,7 @@
   root->ShowRootWindow();
   // Activate new root for testing.
   active_root_window_ = root;
+  aura::client::SetEventClient(root, event_client_.get());

[Ben Goodger (Google), 2012/10/30 02:10:25]

this should probably be done in rootwindowcontroller. that way you'll catch all
of them.

 }
 
 void Shell::DoInitialWorkspaceAnimation() {
@@ -802,4 +803,12 @@
   return false;
 }
 
+bool Shell::CanAcceptEvents() {
+  return true;
+}
+
+ui::EventTarget* Shell::GetParentTarget() {
+  return NULL;
+}
+
 }  // namespace ash