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

content/browser/compositor/gpu_process_transport_factory.cc

Index: content/browser/compositor/gpu_process_transport_factory.cc
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index 7d1cf0c2d283a6620d1de210bc8fc8348d66ee4d..2f90247c3e65dfdb3c3a854f0e4ba363802e0fd2 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -519,7 +519,8 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
                 base::MakeUnique<MusBrowserCompositorOutputSurface>(
                     compositor->window(), context_provider,
                     GetGpuMemoryBufferManager(), compositor->vsync_manager(),
-                    begin_frame_source.get(), std::move(validator));
+                    begin_frame_source.get(), std::move(validator),
+                    compositor->device_scale_factor());
           } else {
             aura::WindowTreeHost* host =
                 aura::WindowTreeHost::GetForAcceleratedWidget(
@@ -528,7 +529,8 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
                 base::MakeUnique<MusBrowserCompositorOutputSurface>(
                     host->window(), context_provider,
                     GetGpuMemoryBufferManager(), compositor->vsync_manager(),
-                    begin_frame_source.get(), std::move(validator));
+                    begin_frame_source.get(), std::move(validator),
+                    compositor->device_scale_factor());
           }
 #else
           NOTREACHED();