Remove return bool in SurfaceOzoneEGL::OnSwapBuffersAsync

ui/ozone/platform/cast/surface_ozone_egl_cast.h

Index: ui/ozone/platform/cast/surface_ozone_egl_cast.h
diff --git a/ui/ozone/platform/cast/surface_ozone_egl_cast.h b/ui/ozone/platform/cast/surface_ozone_egl_cast.h
index 197ef0b697c8acd5e31516ceb32ad1fd3fcdcd95..964b845813dc781f77df69d686da50579e2917d7 100644
--- a/ui/ozone/platform/cast/surface_ozone_egl_cast.h
+++ b/ui/ozone/platform/cast/surface_ozone_egl_cast.h
@@ -20,7 +20,7 @@ class SurfaceOzoneEglCast : public SurfaceOzoneEGL {
   // SurfaceOzoneEGL implementation:
   intptr_t GetNativeWindow() override;
   bool OnSwapBuffers() override;
-  bool OnSwapBuffersAsync(const SwapCompletionCallback& callback) override;
+  void OnSwapBuffersAsync(const SwapCompletionCallback& callback) override;
   bool ResizeNativeWindow(const gfx::Size& viewport_size) override;
   scoped_ptr<gfx::VSyncProvider> CreateVSyncProvider() override;