Stabilize empty rect handling in EnclosingRect.

ui/gfx/geometry/rect_conversions.cc

Index: ui/gfx/geometry/rect_conversions.cc
diff --git a/ui/gfx/geometry/rect_conversions.cc b/ui/gfx/geometry/rect_conversions.cc
index b4ef3d44ec9c4e434b93ae64531cde2f6197014e..fbb51f3cd9ecaa77e254b1c74597a4b860049067 100644
--- a/ui/gfx/geometry/rect_conversions.cc
+++ b/ui/gfx/geometry/rect_conversions.cc
@@ -12,19 +12,22 @@
 
 namespace gfx {
 
+// This is the minimum size of a float rect dimension for use to include it
+// in the enclosing int rect.
+static const float kEmptyDimension = 0.1f;

[Peter Mayo, 2017/03/20 18:53:50]

That is too big - it causes unittests to fail. (occlusion tests)

.09 is empirically enough to make the tests pass.

Interesting.

 Rect ToEnclosingRect(const RectF& rect) {
   int min_x = ToFlooredInt(rect.x());
   int min_y = ToFlooredInt(rect.y());
   float max_x = rect.right();
   float max_y = rect.bottom();
   int width =
-      rect.width() == 0
+      rect.width() < kEmptyDimension
           ? 0
           : std::max(
                 ToCeiledInt(static_cast<double>(ToCeiledInt(max_x)) - min_x),
                 0);
   int height =
-      rect.height() == 0
+      rect.height() < kEmptyDimension
           ? 0
           : std::max(
                 ToCeiledInt(static_cast<double>(ToCeiledInt(max_y)) - min_y),