Enable display rotation, magnifier in unified desktop mode

ash/host/transformer_helper.h

 // Copyright 2014 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_HOST_TRANSFORMER_HELPER_H_
 #define ASH_HOST_TRANSFORMER_HELPER_H_
 
 #include "base/memory/scoped_ptr.h"
 
 namespace gfx {
 class Insets;
 class Size;
 class Transform;
 }
 
 namespace ash {
 class AshWindowTreeHost;
 class RootWindowTransformer;
 
 // A helper class to handle ash specific feature that requires
 // transforming a root window (such as rotation, UI zooming).
 class TransformerHelper {
  public:
   explicit TransformerHelper(AshWindowTreeHost* ash_host);
   ~TransformerHelper();
 
+  // Initializes the transformer with identity transform.
+  void Init();
+
   // Returns the the insets that specifies the effective root window
   // area within the host window.
   gfx::Insets GetHostInsets() const;
 
   // Sets a simple transform with no host insets.
   void SetTransform(const gfx::Transform& transform);
 
   // Sets a RootWindowTransformer which takes the insets into account.
   void SetRootWindowTransformer(scoped_ptr<RootWindowTransformer> transformer);
 
   // Returns the transforms applied to the root window.
   gfx::Transform GetTransform() const;
   gfx::Transform GetInverseTransform() const;
 
   // Updates the root window size based on the host size and
   // current transform.
   void UpdateWindowSize(const gfx::Size& host_size);
 
  private:
   AshWindowTreeHost* ash_host_;
   scoped_ptr<RootWindowTransformer> transformer_;
 
   DISALLOW_COPY_AND_ASSIGN(TransformerHelper);
 };
 
 }  // namespace ash
 
 #endif  // ASH_HOST_TRANSFORMER_HELPER_H_