Virtual context MakeCurrent tweaks.

content/common/gpu/image_transport_surface_mac.cc

Index: content/common/gpu/image_transport_surface_mac.cc
diff --git a/content/common/gpu/image_transport_surface_mac.cc b/content/common/gpu/image_transport_surface_mac.cc
index c6511046901ff3f949b1168f058c10dd8d717a5f..1a09be004771b726ebc1b812e3c71068727825cd 100644
--- a/content/common/gpu/image_transport_surface_mac.cc
+++ b/content/common/gpu/image_transport_surface_mac.cc
@@ -6,6 +6,7 @@
 
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/common/gpu/gpu_command_buffer_stub.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gl/gl_bindings.h"
@@ -33,8 +34,10 @@ int RoundUpSurfaceDimension(int number) {
 
 // We are backed by an offscreen surface for the purposes of creating
 // a context, but use FBOs to render to texture backed IOSurface
-class IOSurfaceImageTransportSurface : public gfx::NoOpGLSurfaceCGL,
-                                       public ImageTransportSurface {
+class IOSurfaceImageTransportSurface
+    : public gfx::NoOpGLSurfaceCGL,
+      public ImageTransportSurface,
+      public GpuCommandBufferStub::DestructionObserver {
  public:
   IOSurfaceImageTransportSurface(GpuChannelManager* manager,
                                  GpuCommandBufferStub* stub,
@@ -62,6 +65,9 @@ class IOSurfaceImageTransportSurface : public gfx::NoOpGLSurfaceCGL,
   virtual void OnResize(gfx::Size size, float scale_factor) OVERRIDE;
   virtual void SetLatencyInfo(const ui::LatencyInfo&) OVERRIDE;
 
+  // GpuCommandBufferStub::DestructionObserver implementation.
+  virtual void OnWillDestroyStub() OVERRIDE;
+
  private:
   virtual ~IOSurfaceImageTransportSurface() OVERRIDE;
 
@@ -101,6 +107,8 @@ class IOSurfaceImageTransportSurface : public gfx::NoOpGLSurfaceCGL,
 
   scoped_ptr<ImageTransportHelper> helper_;
 
+  bool added_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(IOSurfaceImageTransportSurface);
 };
 
@@ -133,12 +141,12 @@ IOSurfaceImageTransportSurface::IOSurfaceImageTransportSurface(
       scale_factor_(1.f),
       made_current_(false),
       is_swap_buffers_pending_(false),
-      did_unschedule_(false) {
+      did_unschedule_(false),
+      added_observer_(false) {
   helper_.reset(new ImageTransportHelper(this, manager, stub, handle));
 }
 
 IOSurfaceImageTransportSurface::~IOSurfaceImageTransportSurface() {
-  Destroy();
 }
 
 bool IOSurfaceImageTransportSurface::Initialize() {
@@ -313,6 +321,11 @@ void IOSurfaceImageTransportSurface::SetLatencyInfo(
   latency_info_ = latency_info;
 }
 
+void IOSurfaceImageTransportSurface::OnWillDestroyStub() {
+  helper_->stub()->RemoveDestructionObserver(this);
+  Destroy();
+}
+
 void IOSurfaceImageTransportSurface::UnrefIOSurface() {
   // If we have resources to destroy, then make sure that we have a current
   // context which we can use to delete the resources.
@@ -340,6 +353,11 @@ void IOSurfaceImageTransportSurface::CreateIOSurface() {
   gfx::Size new_rounded_size(RoundUpSurfaceDimension(size_.width()),
                              RoundUpSurfaceDimension(size_.height()));
 
+  if (!added_observer_) {
+    helper_->stub()->AddDestructionObserver(this);

[piman, 2013/06/05 00:05:33]

Why not do that always in Initialize?
Destroy seems to be doing more than just destroying the surface, and also that
would remove the need for the extra bool.

[no sievers, 2013/06/05 00:19:05]

Done.

I think I was under the false impression that you cannot get to the stub yet
during Init(). But looking at the code that does not seem to be a problem at
all.

+    added_observer_ = true;
+  }
+
   // Only recreate surface when the rounded up size has changed.
   if (io_surface_.get() && new_rounded_size == rounded_size_)
     return;