Fix assorted issues with remote CoreAnimation

content/common/gpu/image_transport_surface_fbo_mac.mm

Index: content/common/gpu/image_transport_surface_fbo_mac.mm
diff --git a/content/common/gpu/image_transport_surface_fbo_mac.mm b/content/common/gpu/image_transport_surface_fbo_mac.mm
index fc7e5ec4bf370933a39cd3ebca0a647539d8b82e..343ee83bfc09647526c2c700ba1e6c8632fd8f22 100644
--- a/content/common/gpu/image_transport_surface_fbo_mac.mm
+++ b/content/common/gpu/image_transport_surface_fbo_mac.mm
@@ -28,8 +28,7 @@ ImageTransportSurfaceFBO::ImageTransportSurfaceFBO(
       context_(NULL),
       scale_factor_(1.f),
       made_current_(false),
-      is_swap_buffers_pending_(false),
-      did_unschedule_(false) {
+      is_swap_buffers_send_pending_(false) {
   if (ui::RemoteLayerAPISupported())
     storage_provider_.reset(new CALayerStorageProvider(this));
   else
@@ -62,17 +61,9 @@ void ImageTransportSurfaceFBO::Destroy() {
 }
 
 bool ImageTransportSurfaceFBO::DeferDraws() {
-  // The command buffer hit a draw/clear command that could clobber the
-  // IOSurface in use by an earlier SwapBuffers. If a Swap is pending, abort
-  // processing of the command by returning true and unschedule until the Swap
-  // Ack arrives.
-  if(did_unschedule_)
-    return true;  // Still unscheduled, so just return true.
-  if (is_swap_buffers_pending_) {
-    did_unschedule_ = true;
-    helper_->SetScheduled(false);
-    return true;
-  }
+  storage_provider_->WillWriteToBackbuffer();
+  // We should not have a pending send when we are drawing the next frame.
+  DCHECK(!is_swap_buffers_send_pending_);

[piman, 2014/08/27 22:13:05]

Is that DCHECK also invalid while the TODO in
CALayerStorageProvider::WillWriteToBackbuffer is in place?

[ccameron, 2014/08/27 22:46:08]

This is still valid.

At the moment it is valid, because the browser will respect the rule "don't
issue any additional GPU commands until you have received the IPC telling you
that the last frame is ready".

After the subsequent CL (still in the works), it will either be invalid (b/c the
browser will stop respecting this), or it will still be valid (because, even
though the browser doesn't respect this, the WillWriteToBackbuffer will issue
the IPC anyway). I have to see which way that will go (not certain yet).

But for now, this is valid.

   return false;
 }
 
@@ -101,6 +92,8 @@ bool ImageTransportSurfaceFBO::SetBackbufferAllocation(bool allocation) {
     return true;
   backbuffer_suggested_allocation_ = allocation;
   AdjustBufferAllocation();
+  if (!allocation)
+    storage_provider_->DiscardBackbuffer();
   return true;
 }
 
@@ -130,18 +123,22 @@ bool ImageTransportSurfaceFBO::SwapBuffers() {
     return true;
   glFlush();
 
+  // It is the responsibility of the storage provider to send the swap IPC.
+  is_swap_buffers_send_pending_ = true;
+  storage_provider_->SwapBuffers(size_, scale_factor_);
+  return true;
+}
+
+void ImageTransportSurfaceFBO::SendSwapBuffers(uint64 surface_handle,
+                                               const gfx::Size pixel_size,
+                                               float scale_factor) {
   GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
-  params.surface_handle = storage_provider_->GetSurfaceHandle();
-  params.size = GetSize();
-  params.scale_factor = scale_factor_;
+  params.surface_handle = surface_handle;
+  params.size = pixel_size;
+  params.scale_factor = scale_factor;
   params.latency_info.swap(latency_info_);
   helper_->SendAcceleratedSurfaceBuffersSwapped(params);
-
-  DCHECK(!is_swap_buffers_pending_);
-  is_swap_buffers_pending_ = true;
-
-  storage_provider_->WillSwapBuffers();
-  return true;
+  is_swap_buffers_send_pending_ = false;
 }
 
 bool ImageTransportSurfaceFBO::PostSubBuffer(
@@ -170,16 +167,7 @@ void* ImageTransportSurfaceFBO::GetDisplay() {
 void ImageTransportSurfaceFBO::OnBufferPresented(
     const AcceleratedSurfaceMsg_BufferPresented_Params& params) {
   context_->share_group()->SetRendererID(params.renderer_id);
-  storage_provider_->CanFreeSwappedBuffer();
-}
-
-void ImageTransportSurfaceFBO::UnblockContextAfterPendingSwap() {
-  DCHECK(is_swap_buffers_pending_);
-  is_swap_buffers_pending_ = false;
-  if (did_unschedule_) {
-    did_unschedule_ = false;
-    helper_->SetScheduled(true);
-  }
+  storage_provider_->SwapBuffersAckedByBrowser();
 }
 
 void ImageTransportSurfaceFBO::OnResize(gfx::Size size,