Fix screen mirroring on Chrome OS (ReflectorTexture partial swap)

content/browser/compositor/gpu_browser_compositor_output_surface.cc

 // Copyright 2014 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/gpu_browser_compositor_output_surface.h"
 
 #include <utility>
 
 #include "build/build_config.h"
 #include "cc/output/output_surface_client.h"
@@ skipping 90 matching lines @@
   context_provider()->ContextGL()->ResizeCHROMIUM(
       size.width(), size.height(), device_scale_factor, has_alpha);
 }
 
 void GpuBrowserCompositorOutputSurface::SwapBuffers(
     cc::OutputSurfaceFrame frame) {
   GetCommandBufferProxy()->SetLatencyInfo(frame.latency_info);
 
   gfx::Size surface_size = frame.size;
   if (reflector_) {
-    if (frame.sub_buffer_rect) {
+    if (frame.sub_buffer_rect && reflector_texture_->is_texture_defined()) {

[danakj, 2017/04/03 19:30:56]

Looks like this bool could live on this class here instead?

       reflector_texture_->CopyTextureSubImage(*frame.sub_buffer_rect);
       reflector_->OnSourcePostSubBuffer(*frame.sub_buffer_rect, surface_size);
     } else {
       reflector_texture_->CopyTextureFullImage(surface_size);
       reflector_->OnSourceSwapBuffers(surface_size);
     }
   }
 
   set_draw_rectangle_for_frame_ = false;
 
@@ skipping 47 matching lines @@
 GpuBrowserCompositorOutputSurface::GetCommandBufferProxy() {
   ui::ContextProviderCommandBuffer* provider_command_buffer =
       static_cast<ui::ContextProviderCommandBuffer*>(context_provider_.get());
   gpu::CommandBufferProxyImpl* command_buffer_proxy =
       provider_command_buffer->GetCommandBufferProxy();
   DCHECK(command_buffer_proxy);
   return command_buffer_proxy;
 }
 
 }  // namespace content