Decouple EventClientImpl and root window. Check containers on the same root window as focused windo…

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 3627616f794080c682bfccd2f5e06b325d2f8a1f..9de3e0918b66331d66c866ee55f098d6613fafdd 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -256,6 +256,7 @@ Shell::~Shell() {
   resize_shadow_controller_.reset();
   shadow_controller_.reset();
   tooltip_controller_.reset();
+  event_client_.reset();
   window_cycle_controller_.reset();
   capture_controller_.reset();
   nested_dispatcher_controller_.reset();
@@ -348,6 +349,12 @@ aura::Window* Shell::GetContainer(aura::RootWindow* root_window,
 }
 
 // static
+const aura::Window* Shell::GetContainer(const aura::RootWindow* root_window,
+                                        int container_id) {
+  return root_window->GetChildById(container_id);
+}
+
+// static
 std::vector<aura::Window*> Shell::GetAllContainers(int container_id) {
   std::vector<aura::Window*> containers;
   aura::Window* container = GetPrimaryRootWindow()->GetChildById(container_id);
@@ -448,6 +455,8 @@ void Shell::Init() {
       drag_drop_controller_.get()));
   AddEnvEventFilter(tooltip_controller_.get());
 
+  event_client_.reset(new internal::EventClientImpl);
+
   InitRootWindowController(root_window_controller);
 
   // This controller needs to be set before SetupManagedWindowMode.
@@ -731,6 +740,7 @@ void Shell::InitRootWindowController(
                                         screen_position_controller_.get());
   aura::client::SetCursorClient(root_window, &cursor_manager_);
   aura::client::SetTooltipClient(root_window, tooltip_controller_.get());
+  aura::client::SetEventClient(root_window, event_client_.get());
 
   if (nested_dispatcher_controller_.get()) {
     aura::client::SetDispatcherClient(root_window,