Bug 1321412 - Add Min() and Max() functions to BaseSize. r=kats

MozReview-Commit-ID: 6GTzkpwwDNu

--HG--
extra : rebase_source : 1d8e888649c10f8f044f475095cb592538992946

gfx/2d/BaseSize.h

@@ -6,6 +6,7 @@
 #ifndef MOZILLA_GFX_BASESIZE_H_
 #define MOZILLA_GFX_BASESIZE_H_
 
+#include <algorithm>
 #include "mozilla/Attributes.h"
 
 namespace mozilla {
@@ -92,6 +93,16 @@ struct BaseSize {
   Sub operator/(const Sub& aSize) const {
     return Sub(width / aSize.width, height / aSize.height);
   }
+
+  friend Sub Min(const Sub& aA, const Sub& aB) {
+    return Sub(std::min(aA.width, aB.width),
+               std::min(aA.height, aB.height));
+  }
+
+  friend Sub Max(const Sub& aA, const Sub& aB) {
+    return Sub(std::max(aA.width, aB.width),
+               std::max(aA.height, aB.height));
+  }
 };
 
 } // namespace gfx