MenuButton: support Mac look & feel

ui/gfx/scoped_canvas.h

 // Copyright 2013 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 UI_GFX_SCOPED_CANVAS_H_
 #define UI_GFX_SCOPED_CANVAS_H_
 
 #include "base/macros.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/geometry/rect.h"

[tapted, 2016/04/22 13:46:52]

forward-declare?

[Elly Fong-Jones, 2016/04/25 14:30:50]

Done.

 
 namespace gfx {
 
 // Saves the drawing state, and restores the state when going out of scope.
 class ScopedCanvas {
  public:
   explicit ScopedCanvas(gfx::Canvas* canvas) : canvas_(canvas) {
     if (canvas_)
       canvas_->Save();
   }
   ~ScopedCanvas() {
     if (canvas_)
       canvas_->Restore();
   }
 
  private:
   gfx::Canvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedCanvas);
 };
 
+// Saves the drawing state, and applies an RTL transform for the supplied rect
+// if the UI is in RTL layout. The resulting transform is such that anything
+// drawn inside the supplied rect will be flipped RTL.

[tapted, 2016/04/22 13:46:52]

nit: replace `flipped RTL` with `horizontally flipped`.

(to me at least, "RTL" seems like a concept of it's own, rather than something
that should be spoken "right to left")

[Elly Fong-Jones, 2016/04/25 14:30:50]

Done.

+

[tapted, 2016/04/22 13:46:52]

nit: remove blank line

[Elly Fong-Jones, 2016/04/25 14:30:50]

Done.

+class ScopedRTLFlipCanvas {
+ public:
+  ScopedRTLFlipCanvas(gfx::Canvas* canvas, gfx::Rect rect);

[tapted, 2016/04/22 13:46:52]

nit: const-ref on `rect`

[Elly Fong-Jones, 2016/04/25 14:30:50]

Done.

+  ~ScopedRTLFlipCanvas() {}
+
+ private:
+  ScopedCanvas canvas_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedRTLFlipCanvas);
+};
+
 }  // namespace gfx
 
 #endif  // UI_GFX_SCOPED_CANVAS_H_