Add the partial screen magnifier to Chrome OS.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 41ce0dd2019367fc0f6d46e690fb19a4a1032177..26cbd6749d4f7a29f48025e59cd608aeb16bd888 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -66,7 +66,9 @@ class DesktopBackgroundController;
 class DisplayController;
 class HighContrastController;
 class Launcher;
+class MagnificationController;
 class NestedDispatcherController;
+class PartialMagnificationController;
 class PowerButtonController;
 class ScreenAsh;
 class SessionStateController;
@@ -89,7 +91,6 @@ class DragDropController;
 class EventClientImpl;
 class EventRewriterEventFilter;
 class FocusCycler;
-class MagnificationController;
 class MouseCursorEventFilter;
 class OutputConfiguratorAnimation;
 class OverlayEventFilter;
@@ -322,10 +323,14 @@ class ASH_EXPORT Shell : internal::SystemModalContainerEventFilterDelegate,
     return high_contrast_controller_.get();
   }
 
-  internal::MagnificationController* magnification_controller() {
+  MagnificationController* magnification_controller() {
     return magnification_controller_.get();
   }
 
+  PartialMagnificationController* partial_magnification_controller() {
+    return partial_magnification_controller_.get();
+  }
+
   const ScreenAsh* screen() { return screen_; }
 
   // Force the shelf to query for it's current visibility state.
@@ -486,7 +491,8 @@ class ASH_EXPORT Shell : internal::SystemModalContainerEventFilterDelegate,
   scoped_ptr<internal::FocusCycler> focus_cycler_;
   scoped_ptr<DisplayController> display_controller_;
   scoped_ptr<HighContrastController> high_contrast_controller_;
-  scoped_ptr<internal::MagnificationController> magnification_controller_;
+  scoped_ptr<MagnificationController> magnification_controller_;
+  scoped_ptr<PartialMagnificationController> partial_magnification_controller_;
   scoped_ptr<aura::FocusManager> focus_manager_;
   scoped_ptr<aura::client::UserActionClient> user_action_client_;
   scoped_ptr<internal::MouseCursorEventFilter> mouse_cursor_filter_;