[ozone] Add stub async swap buffers implementation to ozone surfaceless.

ui/gl/gl_surface_ozone.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 "ui/gl/gl_surface.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gl/gl_context.h"
@@ skipping 124 matching lines @@
         widget_, z_order, transform, bounds_rect, crop_rect);
   }
   bool IsOffscreen() override { return false; }
   VSyncProvider* GetVSyncProvider() override { return vsync_provider_.get(); }
   bool SupportsPostSubBuffer() override { return true; }
   bool PostSubBuffer(int x, int y, int width, int height) override {
     // The actual sub buffer handling is handled at higher layers.
     SwapBuffers();
     return true;
   }
+  bool SwapBuffersAsync(const SwapCompletionCallback& callback) override {
+    // TODO: this should be replaced by a fence when supported by the driver.
+    glFlush();
+    return ozone_surface_->OnSwapBuffersAsync(callback);
+  }
+  bool PostSubBufferAsync(int x,
+                          int y,
+                          int width,
+                          int height,
+                          const SwapCompletionCallback& callback) override {
+    return SwapBuffersAsync(callback);
+  }
 
  private:
   virtual ~GLSurfaceOzoneSurfaceless() {
     Destroy();  // EGL surface must be destroyed before SurfaceOzone
   }
 
   // The native surface. Deleting this is allowed to free the EGLNativeWindow.
   scoped_ptr<ui::SurfaceOzoneEGL> ozone_surface_;
   AcceleratedWidget widget_;
   scoped_ptr<VSyncProvider> vsync_provider_;
@@ skipping 90 matching lines @@
       NOTREACHED();
       return NULL;
   }
 }
 
 EGLNativeDisplayType GetPlatformDefaultEGLNativeDisplay() {
   return ui::SurfaceFactoryOzone::GetInstance()->GetNativeDisplay();
 }
 
 }  // namespace gfx