Provide gtest printers for ui/gfx geometry types

ui/gfx/transform.h

Index: ui/gfx/transform.h
diff --git a/ui/gfx/transform.h b/ui/gfx/transform.h
index 5440aac71f5bffa891d5ed16db392830009a77c4..96104fee4a6ebc3a25a0a33787bb82e9970cd737 100644
--- a/ui/gfx/transform.h
+++ b/ui/gfx/transform.h
@@ -5,6 +5,7 @@
 #ifndef UI_GFX_TRANSFORM_H_
 #define UI_GFX_TRANSFORM_H_
 
+#include <iosfwd>
 #include <string>
 
 #include "base/compiler_specific.h"
@@ -268,6 +269,11 @@ class GFX_EXPORT Transform {
   // copy/assign are allowed.
 };
 
+// This is declared here for use in gtest-based unit tests but is defined in
+// the gfx_test_support target. Depend on that to use this in your unit test.
+// This should not be used in production code - call ToString() instead.
+void PrintTo(const Transform& transform, ::std::ostream* os);
+
 }  // namespace gfx
 
 #endif  // UI_GFX_TRANSFORM_H_