Make exo::Surface set device_scale_factor.

components/exo/surface.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 COMPONENTS_EXO_SURFACE_H_
 #define COMPONENTS_EXO_SURFACE_H_
 
 #include <list>
 #include <memory>
 #include <set>
@@ skipping 122 matching lines @@
   // This sets the only visible on secure output flag, preventing it from
   // appearing in screenshots or from being viewed on non-secure displays.
   void SetOnlyVisibleOnSecureOutput(bool only_visible_on_secure_output);
 
   // This sets the blend mode that will be used when drawing the surface.
   void SetBlendMode(SkBlendMode blend_mode);
 
   // This sets the alpha value that will be applied to the whole surface.
   void SetAlpha(float alpha);
 
+  // This sets the device scale factor sent in CompositorFrames.
+  void SetDeviceScaleFactor(float device_scale_factor);
+
   // Surface state (damage regions, attached buffers, etc.) is double-buffered.
   // A Commit() call atomically applies all pending state, replacing the
   // current state. Commit() is not guaranteed to be synchronous. See
   // CommitSurfaceHierarchy() below.
   void Commit();
 
   // This will synchronously commit all pending state of the surface and its
   // descendants by recursively calling CommitSurfaceHierarchy() for each
   // sub-surface with pending state.
   void CommitSurfaceHierarchy();
@@ skipping 154 matching lines @@
   // This is the size of the last committed contents.
   gfx::Size content_size_;
 
   // This is true when Attach() has been called and new contents should take
   // effect next time Commit() is called.
   bool has_pending_contents_ = false;
 
   // The buffer that will become the content of surface when Commit() is called.
   BufferAttachment pending_buffer_;
 
+  // The device scale factor sent in CompositorFrames.
+  float device_scale_factor_ = 1.0f;

[reveman, 2017/04/27 21:01:30]

Did you verify that this is updated as the |windiow_| is added to the window
hierarchy?

[kylechar, 2017/04/28 18:02:16]

It gets updated when the ui::Layer with |window_| as it's delegate gets added to
the LayerTree. It looks like UpdateSurface() can get called once or twice before
that happens, but since the ui::Layer isn't in the tree yet I don't think those
CompositorFrames would be embedded anywhere?

Does exo use ui::SurfaceLayers to embed content or is something special going on
with those fullscreen exo::Surfaces?

[reveman, 2017/04/28 18:06:49]

Sounds good. UpdateSurface calls before delegate is added to the tree should not
produce any contents so we should be fine.
We always use ui::SurfaceLayers afaik.

+
   const cc::FrameSinkId frame_sink_id_;
   cc::LocalSurfaceId local_surface_id_;
 
   scoped_refptr<CompositorFrameSinkHolder> compositor_frame_sink_holder_;
 
   cc::LocalSurfaceIdAllocator id_allocator_;
 
   // The next resource id the buffer will be attached to.
   int next_resource_id_ = 1;
 
@@ skipping 72 matching lines @@
   cc::BeginFrameSource* begin_frame_source_ = nullptr;
   bool needs_begin_frame_ = false;
   cc::BeginFrameAck current_begin_frame_ack_;
 
   DISALLOW_COPY_AND_ASSIGN(Surface);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_SURFACE_H_