Do not convert from RectF to Rect by flooring.

ui/gfx/size_base.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_SIZE_BASE_H_
 #define UI_GFX_SIZE_BASE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 35 matching lines @@
 
   bool operator==(const Class& s) const {
     return width_ == s.width_ && height_ == s.height_;
   }
 
   bool operator!=(const Class& s) const {
     return !(*this == s);
   }
 
   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:
   SizeBase(Type width, Type height);
   // Destructor is intentionally made non virtual and protected.
   // Do not make this public.
   ~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_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_SIZE_BASE_H_