Revert of Avoid two targeting phases in aura client-lib and EventProcessor.

ash/wm/workspace_controller_unittest.cc

Index: ash/wm/workspace_controller_unittest.cc
diff --git a/ash/wm/workspace_controller_unittest.cc b/ash/wm/workspace_controller_unittest.cc
index e51dedc49ee9bf00606cab60a79ce3511efd750e..db4d5869762dff7e0340d9525b72602b0361871e 100644
--- a/ash/wm/workspace_controller_unittest.cc
+++ b/ash/wm/workspace_controller_unittest.cc
@@ -1481,9 +1481,8 @@
   ParentWindowInPrimaryRootWindow(second.get());
   second->Show();
 
-  aura::Window* root = first->GetRootWindow();
-  ui::EventTargeter* targeter =
-      root->GetHost()->dispatcher()->GetDefaultEventTargeter();
+  ui::EventTarget* root = first->GetRootWindow();
+  ui::EventTargeter* targeter = root->GetEventTargeter();
 
   // The windows overlap, and |second| is on top of |first|. Events targeted
   // slightly outside the edges of the |second| window should still be targeted
@@ -1531,9 +1530,8 @@
   aura::test::TestWindowDelegate delegate;
   std::unique_ptr<Window> window(
       CreateTestPanel(&delegate, gfx::Rect(20, 10, 100, 50)));
-  aura::Window* root = window->GetRootWindow();
-  ui::EventTargeter* targeter =
-      root->GetHost()->dispatcher()->GetDefaultEventTargeter();
+  ui::EventTarget* root = window->GetRootWindow();
+  ui::EventTargeter* targeter = root->GetEventTargeter();
   const gfx::Rect bounds = window->bounds();
   const int kNumPoints = 5;
   struct {
@@ -1568,9 +1566,8 @@
   aura::test::TestWindowDelegate delegate;
   std::unique_ptr<Window> window(
       CreateTestPanel(&delegate, gfx::Rect(20, 10, 100, 50)));
-  aura::Window* root = window->GetRootWindow();
-  ui::EventTargeter* targeter =
-      root->GetHost()->dispatcher()->GetDefaultEventTargeter();
+  ui::EventTarget* root = window->GetRootWindow();
+  ui::EventTargeter* targeter = root->GetEventTargeter();
   const gfx::Rect bounds = window->bounds();
   const int kNumPoints = 5;
   struct {
@@ -1610,9 +1607,8 @@
       window->GetRootWindow(), kShellWindowId_DockedContainer);
   docked_container->AddChild(window.get());
   window->Show();
-  aura::Window* root = window->GetRootWindow();
-  ui::EventTargeter* targeter =
-      root->GetHost()->dispatcher()->GetDefaultEventTargeter();
+  ui::EventTarget* root = window->GetRootWindow();
+  ui::EventTargeter* targeter = root->GetEventTargeter();
   const gfx::Rect bounds = window->bounds();
   const int kNumPoints = 5;
   struct {