Clean up HitTestRegionFlags enums.

Bug: none
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel
Change-Id: Iebf99dde5bd1524779c417eb72dbe9e887e2457a
Reviewed-on: https://chromium-review.googlesource.com/1228477Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Ria Jiang <riajiang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592025}

components/viz/common/hit_test/hit_test_region_list.h

@@ -14,26 +14,26 @@
 
 namespace viz {
 
-struct HitTestRegionFlags {
+enum HitTestRegionFlags : uint32_t {
   // Region maps to this surface (me).
-  enum : uint32_t { kHitTestMine = 0x01 };
+  kHitTestMine = 0x01,
   // Region ignored for hit testing (transparent backgrounds & hover:none).
-  enum : uint32_t { kHitTestIgnore = 0x02 };
+  kHitTestIgnore = 0x02,
   // Region maps to child surface (OOPIF).
-  enum : uint32_t { kHitTestChildSurface = 0x04 };
+  kHitTestChildSurface = 0x04,
   // Irregular boundary - send HitTestRequest to resolve.
-  enum : uint32_t { kHitTestAsk = 0x08 };
+  kHitTestAsk = 0x08,
 
   // TODO(varkha): Add other kHitTest* flags as necessary for other event
   // sources such as mouse-wheel, stylus or perhaps even mouse-move.
 
   // Hit-testing for mouse events.
-  enum : uint32_t { kHitTestMouse = 0x10 };
+  kHitTestMouse = 0x10,
   // Hit-testing for touch events.
-  enum : uint32_t { kHitTestTouch = 0x20 };
+  kHitTestTouch = 0x20,
 
   // Client hasn't submitted its own hit-test data yet.
-  enum : uint32_t { kHitTestNotActive = 0x40 };
+  kHitTestNotActive = 0x40,
 };
 
 struct HitTestRegion {