Migrate from MathUtil::inverse() to gfx::Transform::GetInverse()

cc/test/geometry_test_utils.h

 // Copyright 2011 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.
 
 #ifndef CC_TEST_GEOMETRY_TEST_UTILS_H_
 #define CC_TEST_GEOMETRY_TEST_UTILS_H_
 
 namespace gfx {
 class Transform;
 }
@@ skipping 55 matching lines @@
 
 void ExpectTransformationMatrixEq(const WebKit::WebTransformationMatrix& expected,
                                   const WebKit::WebTransformationMatrix& actual);
 
 #define EXPECT_TRANSFORMATION_MATRIX_EQ(expected, actual)            \
     {                                                                \
         SCOPED_TRACE("");                                            \
         cc::ExpectTransformationMatrixEq(expected, actual);          \
     }
 
+// Should be used in test code only, for convenience. Production code should use
+// the gfx::Transform::GetInverse() API.
+gfx::Transform inverse(const gfx::Transform& transform);
+
 }  // namespace cc
 
 #endif  // CC_TEST_GEOMETRY_TEST_UTILS_H_