Bug 1321412 - Add an operator<< to BaseSize. r=kats

MozReview-Commit-ID: 4zVkyafxtfG

--HG--
extra : rebase_source : 4a5a3f09ab0008d7e736cedb817505e6e45b054c

gfx/2d/BaseSize.h

@@ -7,6 +7,8 @@
 #define MOZILLA_GFX_BASESIZE_H_
 
 #include <algorithm>
+#include <ostream>
+
 #include "mozilla/Attributes.h"
 
 namespace mozilla {
@@ -103,6 +105,11 @@ struct BaseSize {
     return Sub(std::max(aA.width, aB.width),
                std::max(aA.height, aB.height));
   }
+
+  friend std::ostream& operator<<(std::ostream& aStream,
+      const BaseSize<T, Sub>& aSize) {
+    return aStream << aSize.width << " x " << aSize.height;
+  }
 };
 
 } // namespace gfx