[Chromecast] Handle device scale factor correctly

chromecast/media/base/video_plane_controller.h

 // Copyright 2015 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 CHROMECAST_MEDIA_VIDEO_PLANE_CONTROLLER_H_
 #define CHROMECAST_MEDIA_VIDEO_PLANE_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
@@ skipping 14 matching lines @@
 //   resolution coordinates
 // * updates VideoPlane when screen resolution changes
 // * handles threading correctly (posting SetGeometry to media thread).
 // * coalesces multiple calls in short space of time to prevent flooding the
 //   media thread with SetGeometry calls (which are expensive on many
 //   platforms).
 // All public methods should be called from the same thread that the class was
 // constructed on.
 class VideoPlaneController {
  public:
-  explicit VideoPlaneController(
+  VideoPlaneController(
+      const Size& graphics_resolution,
       scoped_refptr<base::SingleThreadTaskRunner> media_task_runner);
   ~VideoPlaneController();
   // Sets the video plane geometry in *graphics plane coordinates*. If there is
   // no change to video plane parameters from the last call to this method, it
   // is a no-op.
   void SetGeometry(const RectF& display_rect, VideoPlane::Transform transform);
 
   // Sets physical screen resolution. This must be called at least once when
   // the final output resolution (HDMI signal or panel resolution) is known,
   // then later when it changes. If there is no change to the screen resolution
   // from the last call to this method, it is a no-op.
   void SetScreenResolution(const Size& resolution);
 
   // Sets graphics hardware plane resolution, and clears any cached video plane
   // geometry parameters. This must be called at least once when the hardware
   // graphics plane resolution (same resolution as display::Screen) is known,
   // then later when it changes. If there is no change to the graphics plane
   // resolution from the last call to this method, it is a no-op.
   void SetGraphicsPlaneResolution(const Size& resolution);

[alokp, 2016/05/12 21:35:16]

Now that we pass graphics resolution in the constructor that does not change, do
we still need this method?

[halliwell, 2016/05/13 23:48:03]

Yep, not needed.

 
   // After Pause is called, no further calls to VideoPlane::SetGeometry will be
   // made except for any pending calls already scheduled on the media thread.
   // The Set methods will however update cached parameters that will take
   // effect once the class is resumed. Safe to call multiple times.
   // TODO(esum): Handle the case where there are pending calls already on the
   // media thread. When this returns, the caller needs to know that absolutely
   // no more SetGeometry calls will be made.
   void Pause();
   // Makes class active again, and clears any cached video plane geometry
@@ skipping 34 matching lines @@
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoPlaneController);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_VIDEO_PLANE_CONTROLLER_H_