Make various gfx classes more amenable to use as compile-time constants.

cc/trees/occlusion_tracker_perftest.cc

Index: cc/trees/occlusion_tracker_perftest.cc
diff --git a/cc/trees/occlusion_tracker_perftest.cc b/cc/trees/occlusion_tracker_perftest.cc
index 867544fcce5f82554c882f18d8f50ffaed24a3b7..1550b76390385f05d0cd549b1827d9a266c7f92a 100644
--- a/cc/trees/occlusion_tracker_perftest.cc
+++ b/cc/trees/occlusion_tracker_perftest.cc
@@ -127,7 +127,7 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_FullyOccluded) {
         bool expect_empty =
             query_content_rect.right() <= viewport_rect.width() &&
             query_content_rect.bottom() + 96 <= viewport_rect.height();
-        CHECK_EQ(expect_empty, unoccluded.IsEmpty())
+        ASSERT_EQ(expect_empty, unoccluded.IsEmpty())
             << query_content_rect.ToString();
       }
     }
@@ -188,7 +188,7 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_10OpaqueLayers) {
   LayerIteratorPosition pos = begin;
   tracker.EnterLayer(pos);
   tracker.LeaveLayer(pos);
-
+/* This block doesn't seem to do anything, missing part of the loop body?

[Peter Kasting, 2016/06/10 05:50:06]

Dana, I think you wrote this, want to comment on what needs to be done here?

   gfx::Transform transform_to_target;
   transform_to_target.Translate(0, 96);
 
@@ -200,12 +200,13 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_10OpaqueLayers) {
         gfx::Rect query_content_rect(x, y, 256, 256);
         gfx::Rect unoccluded =
             occlusion.GetUnoccludedContentRect(query_content_rect);
+            occlusion.GetUnoccludedContentRect(query_content_rect);

[Peter Kasting, 2016/06/10 05:50:06]

Oops, ignore this typo line

       }
     }
 
     timer_.NextLap();
   } while (!timer_.HasTimeLimitExpired());
-
+*/
   ++begin;
   LayerIteratorPosition next = begin;
   EXPECT_EQ(active_tree()->root_layer(), next.current_layer);