First crack at implementing the touch explaration mode.

ash/root_window_controller.h

Index: ash/root_window_controller.h
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index abb8b1f51b878829bb6d2246c797880f537819bb..757f325282481eccde91ce0db2eb315a9123f773 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -7,10 +7,13 @@
 
 #include <map>
 
+#include "ash/accessibility_delegate.h"
 #include "ash/ash_export.h"
 #include "ash/shelf/shelf_types.h"
 #include "ash/shell_observer.h"
+#include "ash/system/tray_accessibility.h"
 #include "ash/system/user/login_status.h"
+#include "ash/touch/touch_exploration_controller.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/window.h"
@@ -79,7 +82,8 @@ class BootSplashScreen;
 // The RootWindowController for particular root window is stored in
 // its property (RootWindowSettings) and can be obtained using
 // |GetRootWindowController(aura::WindowEventDispatcher*)| function.
-class ASH_EXPORT RootWindowController : public ShellObserver {
+class ASH_EXPORT RootWindowController : public ShellObserver,
+                                        public AccessibilityObserver {
  public:
 
   // Creates and Initialize the RootWindowController for primary display.
@@ -270,6 +274,12 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
   virtual void OnLoginStateChanged(user::LoginStatus status) OVERRIDE;
   virtual void OnTouchHudProjectionToggled(bool enabled) OVERRIDE;
 
+  void UpdateTouchExplorationState();
+
+  // Overridden from AccessibilityObserver.
+  virtual void OnAccessibilityModeChanged(
+      AccessibilityNotificationVisibility notify) OVERRIDE;
+
   scoped_ptr<aura::WindowTreeHost> host_;
   RootWindowLayoutManager* root_window_layout_;
 
@@ -312,6 +322,8 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
   scoped_ptr<AnimatingDesktopController> animating_wallpaper_controller_;
   scoped_ptr< ::wm::ScopedCaptureClient> capture_client_;
 
+  scoped_ptr<TouchExplorationController> touch_exploration_controller_;
+
   DISALLOW_COPY_AND_ASSIGN(RootWindowController);
 };