Add the partial screen magnifier to Chrome OS.

ash/magnifier/magnification_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/magnifier/magnification_controller.h"
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/event_filter.h"
@@ skipping 29 matching lines @@
 
 class MagnificationControllerImpl : virtual public MagnificationController,
                                     public aura::EventFilter,
                                     public ui::ImplicitAnimationObserver {
  public:
   MagnificationControllerImpl();
   virtual ~MagnificationControllerImpl();
 
   // MagnificationController overrides:
   virtual void SetEnabled(bool enabled) OVERRIDE;
+  virtual bool IsEnabled() const OVERRIDE;
   virtual void SetScale(float scale, bool animate) OVERRIDE;
   virtual float GetScale() const OVERRIDE { return scale_; }
   virtual void MoveWindow(int x, int y, bool animate) OVERRIDE;
   virtual void MoveWindow(const gfx::Point& point, bool animate) OVERRIDE;
   virtual gfx::Point GetWindowPosition() const OVERRIDE { return origin_; }
   virtual void EnsureRectIsVisible(const gfx::Rect& rect,
                                    bool animate) OVERRIDE;
   virtual void EnsurePointIsVisible(const gfx::Point& point,
                                     bool animate) OVERRIDE;
 
@@ skipping 366 matching lines @@
         ash::Shell::GetInstance()->delegate()->GetSavedScreenMagnifierScale();
     ValidateScale(&scale);
     RedrawKeepingMousePosition(scale, true);
     is_enabled_ = enabled;
   } else {
     RedrawKeepingMousePosition(kNonMagnifiedScale, true);
     is_enabled_ = enabled;
   }
 }
 
+bool MagnificationControllerImpl::IsEnabled() const {
+  return is_enabled_;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationControllerImpl: aura::EventFilter implementation
 
 bool MagnificationControllerImpl::PreHandleKeyEvent(aura::Window* target,
                                                     ui::KeyEvent* event) {
   return false;
 }
 
 bool MagnificationControllerImpl::PreHandleMouseEvent(aura::Window* target,
                                                       ui::MouseEvent* event) {
@@ skipping 37 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationController:
 
 // static
 MagnificationController* MagnificationController::CreateInstance() {
   return new MagnificationControllerImpl();
 }
 
 }  // namespace internal
 }  // namespace ash