[Ozone-DRI] Fix waiting for page flips in mirror mode

ui/ozone/platform/dri/test/mock_dri_wrapper.cc

Index: ui/ozone/platform/dri/test/mock_dri_wrapper.cc
diff --git a/ui/ozone/platform/dri/test/mock_dri_wrapper.cc b/ui/ozone/platform/dri/test/mock_dri_wrapper.cc
index b3f0100d1204d2b936fb2ccaeb4195258d41af77..fefddf79403139369ab1b3236a222dfad35a299d 100644
--- a/ui/ozone/platform/dri/test/mock_dri_wrapper.cc
+++ b/ui/ozone/platform/dri/test/mock_dri_wrapper.cc
@@ -30,6 +30,7 @@ MockDriWrapper::MockDriWrapper(int fd)
       remove_framebuffer_call_count_(0),
       page_flip_call_count_(0),
       overlay_flip_call_count_(0),
+      handle_events_count_(0),
       set_crtc_expectation_(true),
       add_framebuffer_expectation_(true),
       page_flip_expectation_(true),
@@ -132,6 +133,7 @@ void MockDriWrapper::HandleEvent(drmEventContext& event) {
   CHECK(!controllers_.empty());
   controllers_.front()->OnPageFlipEvent(0, 0, 0);
   controllers_.pop();
+  handle_events_count_++;
 }
 
 bool MockDriWrapper::CreateDumbBuffer(const SkImageInfo& info,