Partial swap implementation for surfaceless

content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc

Index: content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
diff --git a/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc b/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
index a1e7f54a117e103294fa4a0217e1d53a4983b881..b0c78661a2eb19c3bbe8cfe02d0229b70d370579 100644
--- a/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
+++ b/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
@@ -21,13 +21,15 @@ GpuSurfacelessBrowserCompositorOutputSurface::
         IDMap<BrowserCompositorOutputSurface>* output_surface_map,
         const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager,
         scoped_ptr<cc::OverlayCandidateValidator> overlay_candidate_validator,
+        GLHelper* gl_helper,
         unsigned internalformat)
     : GpuBrowserCompositorOutputSurface(context,
                                         surface_id,
                                         output_surface_map,
                                         vsync_manager,
                                         overlay_candidate_validator.Pass()),
-      internalformat_(internalformat) {
+      internalformat_(internalformat),
+      gl_helper_(gl_helper) {
 }
 
 GpuSurfacelessBrowserCompositorOutputSurface::
@@ -38,6 +40,11 @@ void GpuSurfacelessBrowserCompositorOutputSurface::SwapBuffers(
     cc::CompositorFrame* frame) {
   DCHECK(output_surface_);
 
+  output_surface_->SwapBuffers(frame->gl_frame_data->sub_buffer_rect);
+  // Disable the sub-buffer processing path on the parent classes, because we
+  // have handled it here.
+  frame->gl_frame_data->sub_buffer_rect = gfx::Rect(frame->gl_frame_data->size);
+
   const gfx::Size& size = frame->gl_frame_data->size;
   context_provider_->ContextGL()->ScheduleOverlayPlaneCHROMIUM(
       0,
@@ -51,7 +58,6 @@ void GpuSurfacelessBrowserCompositorOutputSurface::SwapBuffers(
       0,
       1.0f,
       1.0f);
-  output_surface_->SwapBuffers();
   GpuBrowserCompositorOutputSurface::SwapBuffers(frame);
 }
 
@@ -78,7 +84,8 @@ bool GpuSurfacelessBrowserCompositorOutputSurface::BindToClient(
     cc::OutputSurfaceClient* client) {
   if (!GpuBrowserCompositorOutputSurface::BindToClient(client))
     return false;
-  output_surface_.reset(new BufferQueue(context_provider_, internalformat_));
+  output_surface_.reset(
+      new BufferQueue(context_provider_, gl_helper_, internalformat_));
   return output_surface_->Initialize();
 }