cc: DCHECK if SDOS::SwapBuffersComplete is called prematurely

cc/surfaces/surface_display_output_surface.cc

Index: cc/surfaces/surface_display_output_surface.cc
diff --git a/cc/surfaces/surface_display_output_surface.cc b/cc/surfaces/surface_display_output_surface.cc
index e1f90da761421f5a97bbf939f6714c3fa00144a6..cea4c68ca8fcaf75d3c400a72f857e5175c046d3 100644
--- a/cc/surfaces/surface_display_output_surface.cc
+++ b/cc/surfaces/surface_display_output_surface.cc
@@ -5,6 +5,7 @@
 #include "cc/surfaces/surface_display_output_surface.h"
 
 #include "base/bind.h"
+#include "base/debug/stack_trace.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_ack.h"
 #include "cc/surfaces/display.h"
@@ -21,7 +22,8 @@ SurfaceDisplayOutputSurface::SurfaceDisplayOutputSurface(
     : OutputSurface(context_provider),
       display_client_(NULL),
       factory_(surface_manager, this),
-      allocator_(allocator) {
+      allocator_(allocator),
+      inside_swap_buffers_(0) {
   factory_.set_needs_sync_points(false);
   capabilities_.delegated_rendering = true;
   capabilities_.max_frames_pending = 1;
@@ -46,26 +48,36 @@ void SurfaceDisplayOutputSurface::ReceivedVSyncParameters(
 }
 
 void SurfaceDisplayOutputSurface::SwapBuffers(CompositorFrame* frame) {
+  inside_swap_buffers_ = 1;
+
   gfx::Size frame_size =
       frame->delegated_frame_data->render_pass_list.back()->output_rect.size();
   if (frame_size.IsEmpty() || frame_size != display_size_) {
+    inside_swap_buffers_ = 2;
     if (!surface_id_.is_null()) {
       factory_.Destroy(surface_id_);
     }
+    inside_swap_buffers_ = 3;
     surface_id_ = allocator_->GenerateId();
     factory_.Create(surface_id_);
     display_size_ = frame_size;
   }
+  inside_swap_buffers_ = 4;
   display_client_->display()->SetSurfaceId(surface_id_,
                                            frame->metadata.device_scale_factor);
 
+  inside_swap_buffers_ = 5;
   scoped_ptr<CompositorFrame> frame_copy(new CompositorFrame());
+  inside_swap_buffers_ = 6;
   frame->AssignTo(frame_copy.get());
+  inside_swap_buffers_ = 7;
   factory_.SubmitFrame(
       surface_id_, frame_copy.Pass(),
       base::Bind(&SurfaceDisplayOutputSurface::SwapBuffersComplete,
                  base::Unretained(this)));
 
+  inside_swap_buffers_ = 0;
+
   client_->DidSwapBuffers();
 }
 
@@ -92,6 +104,7 @@ void SurfaceDisplayOutputSurface::ReturnResources(
 }
 
 void SurfaceDisplayOutputSurface::SwapBuffersComplete(SurfaceDrawStatus drawn) {
+  DCHECK_EQ(0, inside_swap_buffers_) << base::debug::StackTrace().ToString();
   if (client_ && !display_client_->output_surface_lost())
     client_->DidSwapBuffersComplete();
 }