ozone: Add OnSwapBuffers hook to SurfaceOzoneEGL

ui/ozone/platform/egltest/ozone_platform_egltest.cc

Index: ui/ozone/platform/egltest/ozone_platform_egltest.cc
diff --git a/ui/ozone/platform/egltest/ozone_platform_egltest.cc b/ui/ozone/platform/egltest/ozone_platform_egltest.cc
index 4aa6ea8ad137a40bbfa30841403798560b496dca..8114cb98f5c78f4b2cbd5b829e382a378e16c198 100644
--- a/ui/ozone/platform/egltest/ozone_platform_egltest.cc
+++ b/ui/ozone/platform/egltest/ozone_platform_egltest.cc
@@ -59,6 +59,8 @@ class SurfaceOzoneEgltest : public gfx::SurfaceOzoneEGL {
 
   virtual intptr_t GetNativeWindow() OVERRIDE { return native_window_; }
 
+  virtual bool OnSwapBuffers() OVERRIDE { return true; }
+
   virtual bool ResizeNativeWindow(const gfx::Size& viewport_size) OVERRIDE {
     return true;
   }