Add the partial screen magnifier to Chrome OS.

ash/magnifier/partial_magnification_controller.h

Index: ash/magnifier/partial_magnification_controller.h
diff --git a/ash/magnifier/partial_magnification_controller.h b/ash/magnifier/partial_magnification_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..fe4e5a3f7fa72af6d3c5cc87160c37974b04aa9e
--- /dev/null
+++ b/ash/magnifier/partial_magnification_controller.h
@@ -0,0 +1,51 @@
+// 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.
+
+#ifndef ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_
+#define ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_
+
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/aura/event_filter.h"
+#include "ui/gfx/point.h"
+#include "ui/gfx/rect.h"

[oshima, 2012/09/07 22:30:55]

clean up unused headers

[Zachary Kuznia, 2012/09/13 11:49:02]

Done.

+
+namespace aura {
+class RootWindow;
+}
+
+namespace ash {
+namespace internal {
+
+const float kDefaultPartialMagnifiedScale = 1.5f;
+const float kNonPartialMagnifiedScale = 1.0f;
+
+class PartialMagnificationController {

[sky, 2012/09/07 16:06:59]

Description.

[Zachary Kuznia, 2012/09/13 11:49:02]

Done.

+ public:
+  virtual ~PartialMagnificationController() {}
+
+  // Creates a new PartialMagnificationController. The caller takes ownership
+  // of the returned object.
+  static PartialMagnificationController* CreateInstance();
+
+  // Enables (or disables if |enabled| is false) partial screen magnifier
+  // feature.
+  virtual void SetEnabled(bool enabled) = 0;
+
+  virtual bool IsEnabled() = 0;
+
+  // Sets the magnification ratio. 1.0f means no magnification.
+  virtual void SetScale(float scale) = 0;
+  // Returns the current magnification ratio.
+  virtual float GetScale() const = 0;
+
+ protected:
+  PartialMagnificationController() {}
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_