Provide gtest printers for ui/gfx geometry types

ui/gfx/geometry/vector2d.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Defines a simple integer vector class.  This class is used to indicate a
 // distance in two dimensions between two points. Subtracting two points should
 // produce a vector, and adding a vector to a point produces the point at the
 // vector's distance from the original point.
 
 #ifndef UI_GFX_GEOMETRY_VECTOR2D_H_
 #define UI_GFX_GEOMETRY_VECTOR2D_H_
 
+#include <iosfwd>
 #include <string>
 
 #include "base/basictypes.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 #include "ui/gfx/gfx_export.h"
 
 namespace gfx {
 
 class GFX_EXPORT Vector2d {
  public:
@@ skipping 56 matching lines @@
   result.Add(rhs);
   return result;
 }
 
 inline Vector2d operator-(const Vector2d& lhs, const Vector2d& rhs) {
   Vector2d result = lhs;
   result.Add(-rhs);
   return result;
 }
 
+// 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 Vector2d& vector, ::std::ostream* os);
+
 }  // namespace gfx
 
 #endif // UI_GFX_GEOMETRY_VECTOR2D_H_