Do not convert from RectF to Rect by flooring.

ui/gfx/size_base.h

Index: ui/gfx/size_base.h
diff --git a/ui/gfx/size_base.h b/ui/gfx/size_base.h
index ef687c697d9dd15bd21837b2b4e10c6ab5b9dbbe..5f94ac5936a5ebc3977c567417a22ab65b9db46d 100644
--- a/ui/gfx/size_base.h
+++ b/ui/gfx/size_base.h
@@ -53,8 +53,15 @@ class UI_EXPORT SizeBase {
   }
 
   bool IsEmpty() const {
-    // Size doesn't allow negative dimensions, so testing for 0 is enough.
-    return (width_ == 0) || (height_ == 0);
+    return (width_ <= 0) || (height_ <= 0);
+  }
+
+  void set_allow_negative_size(bool allow) {
+    allow_negative_size_ = allow;
+  }
+
+  void set_crash_if_negative(bool crash) {
+    crash_if_negative_ = crash;
   }
 
  protected:
@@ -64,6 +71,8 @@ class UI_EXPORT SizeBase {
   ~SizeBase();
 
  private:
+  bool allow_negative_size_;

[sky, 2012/09/27 17:48:30]

Having special cases where Size is some times negative and some times not is
error prone. It doesn't seem like you're even using this. Remove it.

+  bool crash_if_negative_;
   Type width_;
   Type height_;
 };