ui: Make gfx::Size::Scale() mutate the class. Add gfx::ScaleSize() similar to Rect/Point.

ui/gfx/size_f.h

Index: ui/gfx/size_f.h
diff --git a/ui/gfx/size_f.h b/ui/gfx/size_f.h
index f9ac6bd890e5b5ab7ec4e7d4c880a5c7f4fef84b..45805019ba12ca7fe94f164cc56ba79d8b6f41c7 100644
--- a/ui/gfx/size_f.h
+++ b/ui/gfx/size_f.h
@@ -19,12 +19,12 @@ class UI_EXPORT SizeF : public SizeBase<SizeF, float> {
   SizeF(float width, float height);
   ~SizeF();
 
-  SizeF Scale(float scale) const WARN_UNUSED_RESULT {
-    return Scale(scale, scale);
+  void Scale(float scale) {
+    Scale(scale, scale);
   }
 
-  SizeF Scale(float x_scale, float y_scale) const WARN_UNUSED_RESULT {
-    return SizeF(width() * x_scale, height() * y_scale);
+  void Scale(float x_scale, float y_scale) {
+    SetSize(width() * x_scale, height() * y_scale);
   }
 
   std::string ToString() const;
@@ -38,6 +38,12 @@ inline bool operator!=(const SizeF& lhs, const SizeF& rhs) {
   return !(lhs == rhs);
 }
 
+UI_EXPORT SizeF ScaleSize(const SizeF& p, float x_scale, float y_scale);
+
+inline SizeF ScaleSize(const SizeF& p, float scale) {
+  return ScaleSize(p, scale, scale);
+}
+
 #if !defined(COMPILER_MSVC)
 extern template class SizeBase<SizeF, float>;
 #endif