Revert 164703 - it broke BookmarkBarViewTest8.DNDBackToOriginatingMenu on Chrome OS - Register a separate default ui::EventTarget for Aura (Ash) to ensure that it does not interfere with the

event handling in desktop chrome in Aura. 

On Windows 8 in chrome metro mode we have a desktop chrome process
which runs as a server to the viewer process in Metro. Reusing the default EventTarget across both environments
causes desktop chrome to crash as a number of EventFilters registered on the default EventTarget get called twice.

The Ash specific EventTarget is implemented by the Ash::Shell class. The RootWindow in its GetParentTarget implementation
delegates this call to the EventClient implementation if one exists and if not it returns the default Aura::Env interface.

The EventClient interface is implemented by Ash and has been updated to return the default EventTarget via the new method
GetToplevelEventTarget

Fixes bug http://code.google.com/p/chromium/issues/detail?id=158105

BUG=158105
R=ben
Review URL: https://codereview.chromium.org/11314013

TBR=ananta@chromium.org
Review URL: https://codereview.chromium.org/11301024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@164728 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 4 insertions, 32 deletions

diff --git a/ash/shell.cc b/ash/shell.cc
index 6ab1289..2a2cc58 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -510,11 +510,11 @@ void Shell::Init() {
 }
 
 void Shell::AddEnvEventFilter(aura::EventFilter* filter) {
-  AddPreTargetHandler(filter);
+  aura::Env::GetInstance()->AddPreTargetHandler(filter);
 }
 
 void Shell::RemoveEnvEventFilter(aura::EventFilter* filter) {
-  RemovePreTargetHandler(filter);
+  aura::Env::GetInstance()->RemovePreTargetHandler(filter);
 }
 
 void Shell::ShowContextMenu(const gfx::Point& location_in_screen) {
@@ -802,12 +802,4 @@ bool Shell::CanWindowReceiveEvents(aura::Window* window) {
   return false;
 }
 
-bool Shell::CanAcceptEvents() {
-  return true;
-}
-
-ui::EventTarget* Shell::GetParentTarget() {
-  return NULL;
-}
-
 }  // namespace ash
diff --git a/ash/shell.h b/ash/shell.h
index 0622130..430e0c2 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -18,7 +18,6 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
-#include "ui/base/events/event_target.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/size.h"
@@ -115,8 +114,7 @@ class WorkspaceController;
 //
 // Upon creation, the Shell sets itself as the RootWindow's delegate, which
 // takes ownership of the Shell.
-class ASH_EXPORT Shell : internal::SystemModalContainerEventFilterDelegate,
-                         public ui::EventTarget {
+class ASH_EXPORT Shell : internal::SystemModalContainerEventFilterDelegate{
  public:
   typedef std::vector<aura::RootWindow*> RootWindowList;
   typedef std::vector<internal::RootWindowController*> RootWindowControllerList;
@@ -426,10 +424,6 @@ class ASH_EXPORT Shell : internal::SystemModalContainerEventFilterDelegate,
   // ash::internal::SystemModalContainerEventFilterDelegate overrides:
   virtual bool CanWindowReceiveEvents(aura::Window* window) OVERRIDE;
 
-  // Overridden from ui::EventTarget:
-  virtual bool CanAcceptEvents() OVERRIDE;
-  virtual EventTarget* GetParentTarget() OVERRIDE;
-
   static Shell* instance_;
 
   // If set before the Shell is initialized, the mouse cursor will be hidden
diff --git a/ash/wm/event_client_impl.cc b/ash/wm/event_client_impl.cc
index 8f9a91b..f7fc8b2 100644
--- a/ash/wm/event_client_impl.cc
+++ b/ash/wm/event_client_impl.cc
@@ -38,9 +38,5 @@ bool EventClientImpl::CanProcessEventsWithinSubtree(
   return true;
 }
 
-ui::EventTarget* EventClientImpl::GetToplevelEventTarget() {
-  return Shell::GetInstance();
-}
-
 }  // namespace internal
 }  // namespace ash
diff --git a/ash/wm/event_client_impl.h b/ash/wm/event_client_impl.h
index 897e881..3702709 100644
--- a/ash/wm/event_client_impl.h
+++ b/ash/wm/event_client_impl.h
@@ -24,7 +24,6 @@ class EventClientImpl : public aura::client::EventClient {
   // Overridden from aura::client::EventClient:
   virtual bool CanProcessEventsWithinSubtree(
       const aura::Window* window) const OVERRIDE;
-  virtual ui::EventTarget* GetToplevelEventTarget() OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(EventClientImpl);
 };
diff --git a/ui/aura/client/event_client.h b/ui/aura/client/event_client.h
index 31565e2..077e959 100644
--- a/ui/aura/client/event_client.h
+++ b/ui/aura/client/event_client.h
@@ -21,9 +21,6 @@ class AURA_EXPORT EventClient {
   // Returns true if events can be processed by |window| or any of its children.
   virtual bool CanProcessEventsWithinSubtree(const Window* window) const = 0;
 
-  // Returns the top level EventTarget for the current environment.
-  virtual ui::EventTarget* GetToplevelEventTarget() = 0;
-
  protected:
   virtual ~EventClient() {}
 };
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index b9712bd..0c0b79d 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -452,9 +452,7 @@ void RootWindow::SetTransform(const gfx::Transform& transform) {
 // RootWindow, ui::EventTarget implementation:
 
 ui::EventTarget* RootWindow::GetParentTarget() {
-  return client::GetEventClient(this) ?
-      client::GetEventClient(this)->GetToplevelEventTarget() :
-          Env::GetInstance();
+  return Env::GetInstance();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/ui/aura/root_window_unittest.cc b/ui/aura/root_window_unittest.cc
index 460e4cc..20e7cbb 100644
--- a/ui/aura/root_window_unittest.cc
+++ b/ui/aura/root_window_unittest.cc
@@ -336,10 +336,6 @@ class TestEventClient : public client::EventClient {
     return lock_ ? GetLockWindow()->Contains(window) : true;
   }
 
-  virtual ui::EventTarget* GetToplevelEventTarget() OVERRIDE {
-    return NULL;
-  }
-
   RootWindow* root_window_;
   bool lock_;