cc: Replace Region with SimpleEnclosedRegion for occlusion tracking

cc/test/test_occlusion_tracker.h

Index: cc/test/test_occlusion_tracker.h
diff --git a/cc/test/test_occlusion_tracker.h b/cc/test/test_occlusion_tracker.h
index f244a2d8cfdde5d4ec4639c56d4b250c043e2ba0..1f51d676f9b50bb75a1bbf77eee0b4d86a6460d6 100644
--- a/cc/test/test_occlusion_tracker.h
+++ b/cc/test/test_occlusion_tracker.h
@@ -18,35 +18,37 @@ class TestOcclusionTracker : public OcclusionTracker<LayerType> {
   explicit TestOcclusionTracker(const gfx::Rect& screen_scissor_rect)
       : OcclusionTracker<LayerType>(screen_scissor_rect) {}
 
-  Region occlusion_from_inside_target() const {
+  SimpleEnclosedRegion occlusion_from_inside_target() const {
     return OcclusionTracker<LayerType>::stack_.back()
         .occlusion_from_inside_target;
   }
-  Region occlusion_from_outside_target() const {
+  SimpleEnclosedRegion occlusion_from_outside_target() const {
     return OcclusionTracker<LayerType>::stack_.back()
         .occlusion_from_outside_target;
   }
 
-  Region occlusion_on_contributing_surface_from_inside_target() const {
+  SimpleEnclosedRegion occlusion_on_contributing_surface_from_inside_target()
+      const {
     size_t stack_size = OcclusionTracker<LayerType>::stack_.size();
     if (stack_size < 2)
-      return Region();
+      return SimpleEnclosedRegion();
     return OcclusionTracker<LayerType>::stack_[stack_size - 2]
         .occlusion_from_inside_target;
   }
-  Region occlusion_on_contributing_surface_from_outside_target() const {
+  SimpleEnclosedRegion occlusion_on_contributing_surface_from_outside_target()
+      const {
     size_t stack_size = OcclusionTracker<LayerType>::stack_.size();
     if (stack_size < 2)
-      return Region();
+      return SimpleEnclosedRegion();
     return OcclusionTracker<LayerType>::stack_[stack_size - 2]
         .occlusion_from_outside_target;
   }
 
-  void set_occlusion_from_outside_target(const Region& region) {
+  void set_occlusion_from_outside_target(const SimpleEnclosedRegion& region) {
     OcclusionTracker<LayerType>::stack_.back().occlusion_from_outside_target =
         region;
   }
-  void set_occlusion_from_inside_target(const Region& region) {
+  void set_occlusion_from_inside_target(const SimpleEnclosedRegion& region) {
     OcclusionTracker<LayerType>::stack_.back().occlusion_from_inside_target =
         region;
   }