Set device scale factor in CompositorFrame and scale frame size in WS.

content/browser/compositor/mus_browser_compositor_output_surface.cc

 // Copyright 2016 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.
 
 #include "content/browser/compositor/mus_browser_compositor_output_surface.h"
 
 #include <utility>
 
 #include "cc/output/compositor_frame.h"
 #include "cc/output/output_surface_frame.h"
@@ skipping 11 matching lines @@
 
 namespace content {
 
 MusBrowserCompositorOutputSurface::MusBrowserCompositorOutputSurface(
     ui::Window* window,
     scoped_refptr<ContextProviderCommandBuffer> context,
     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
     scoped_refptr<ui::CompositorVSyncManager> vsync_manager,
     cc::SyntheticBeginFrameSource* begin_frame_source,
     std::unique_ptr<display_compositor::CompositorOverlayCandidateValidator>
-        overlay_candidate_validator)
+        overlay_candidate_validator,
+    float device_scale_factor)
     : GpuBrowserCompositorOutputSurface(std::move(context),
                                         std::move(vsync_manager),
                                         begin_frame_source,
                                         std::move(overlay_candidate_validator)),
-      ui_window_(window) {
+      ui_window_(window),
+      device_scale_factor_(device_scale_factor) {
   ui_compositor_frame_sink_ = ui_window_->RequestCompositorFrameSink(
       ui::mojom::CompositorFrameSinkType::DEFAULT, context,
       gpu_memory_buffer_manager);
   ui_compositor_frame_sink_->BindToClient(this);
 }
 
 MusBrowserCompositorOutputSurface::MusBrowserCompositorOutputSurface(
     aura::Window* window,
     scoped_refptr<ContextProviderCommandBuffer> context,
     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
     scoped_refptr<ui::CompositorVSyncManager> vsync_manager,
     cc::SyntheticBeginFrameSource* begin_frame_source,
     std::unique_ptr<display_compositor::CompositorOverlayCandidateValidator>
-        overlay_candidate_validator)
+        overlay_candidate_validator,
+    float device_scale_factor)
     : GpuBrowserCompositorOutputSurface(std::move(context),
                                         std::move(vsync_manager),
                                         begin_frame_source,
                                         std::move(overlay_candidate_validator)),
-      window_(window) {
+      window_(window),
+      device_scale_factor_(device_scale_factor) {
   aura::WindowPortMus* window_port = aura::WindowPortMus::Get(window_);
   DCHECK(window_port);
   compositor_frame_sink_ = window_port->RequestCompositorFrameSink(
       ui::mojom::CompositorFrameSinkType::DEFAULT, context,
       gpu_memory_buffer_manager);
   compositor_frame_sink_->BindToClient(this);
 }
 
 MusBrowserCompositorOutputSurface::~MusBrowserCompositorOutputSurface() {}
 
 void MusBrowserCompositorOutputSurface::SwapBuffers(
     cc::OutputSurfaceFrame frame) {
   const gfx::Rect bounds = ui_window_ ? gfx::Rect(ui_window_->bounds().size())
                                       : gfx::Rect(window_->bounds().size());
   cc::CompositorFrame ui_frame;
+  ui_frame.metadata.device_scale_factor = device_scale_factor_;

[danakj, 2016/12/06 22:44:27]

What if the device scale changes? It's not fixed for the life of the output
surface. Granted this whole class needs to go away and should not actually ship
to users.. but are you okay with this cuz I don't see it documented in TODOs or
anything like that.

[riajiang, 2016/12/15 18:14:41]

Changed to get the device_scale_factor from the display for window_
(aura::Window) which should be updated when dsf changes.

   ui_frame.metadata.latency_info = std::move(frame.latency_info);
   // Reset latency_info to known empty state after moving contents.
   frame.latency_info.clear();
   const cc::RenderPassId render_pass_id(1, 1);
   std::unique_ptr<cc::RenderPass> pass = cc::RenderPass::Create();
   const bool has_transparent_background = true;
   pass->SetAll(render_pass_id, bounds, bounds, gfx::Transform(),
                has_transparent_background);
   // The SharedQuadState is owned by the SharedQuadStateList
   // shared_quad_state_list.
@@ skipping 118 matching lines @@
 
 const gpu::Mailbox& MusBrowserCompositorOutputSurface::GetMailboxFromResourceId(
     uint32_t id) {
   DCHECK_LT(id, mailboxes_.size());
   DCHECK(std::find(free_resource_ids_.begin(), free_resource_ids_.end(), id) ==
          free_resource_ids_.end());
   return mailboxes_[id];
 }
 
 }  // namespace content