Do not convert from RectF to Rect by flooring.

ui/gfx/size_base_impl.h

Index: ui/gfx/size_base_impl.h
diff --git a/ui/gfx/size_base_impl.h b/ui/gfx/size_base_impl.h
index 4eca7410f075fea8a8ca73e6cf329216e36e2e70..e76748030603042bca2f120ad53d6f855e016749 100644
--- a/ui/gfx/size_base_impl.h
+++ b/ui/gfx/size_base_impl.h
@@ -16,7 +16,9 @@
 namespace gfx {
 
 template<typename Class, typename Type>
-SizeBase<Class, Type>::SizeBase(Type width, Type height) {
+SizeBase<Class, Type>::SizeBase(Type width, Type height)
+    : allow_negative_size_(false),
+      crash_if_negative_(false) {
   set_width(width);
   set_height(height);
 }
@@ -26,8 +28,9 @@ SizeBase<Class, Type>::~SizeBase() {}
 
 template<typename Class, typename Type>
 void SizeBase<Class, Type>::set_width(Type width) {
-  if (width < 0) {
-    NOTREACHED() << "negative width:" << width;
+  if (!allow_negative_size_ && width < 0) {
+    if (crash_if_negative_)
+      NOTREACHED() << "negative width:" << width;
     width = 0;
   }
   width_ = width;
@@ -35,8 +38,9 @@ void SizeBase<Class, Type>::set_width(Type width) {
 
 template<typename Class, typename Type>
 void SizeBase<Class, Type>::set_height(Type height) {
-  if (height < 0) {
-    NOTREACHED() << "negative height:" << height;
+  if (!allow_negative_size_ && height < 0) {
+    if (crash_if_negative_)
+      NOTREACHED() << "negative height:" << height;
     height = 0;
   }
   height_ = height;