cc: Remove forbidden using namespace directives.

cc/math_util_unittest.cc

 // Copyright 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.
 
 #include "config.h"
 
 #include "cc/math_util.h"
 
 #include <cmath>
 
 #include "cc/test/geometry_test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/rect_f.h"
 #include <public/WebTransformationMatrix.h>
 
-using namespace cc;
 using WebKit::WebTransformationMatrix;
 
+namespace cc {
 namespace {
 
 TEST(MathUtilTest, verifyBackfaceVisibilityBasicCases)
 {
     WebTransformationMatrix transform;
 
     transform.makeIdentity();
     EXPECT_FALSE(transform.isBackFaceVisible());
 
     transform.makeIdentity();
@@ skipping 144 matching lines @@
     EXPECT_VECTOR_EQ(gfx::Vector2dF(0, testVector.y()), MathUtil::projectVector(testVector, y));
 
     // Finally check than an arbitrary vector projected to another one gives a vector parallel to
     // the second vector.
     gfx::Vector2dF targetVector(0.5, 0.2f);
     gfx::Vector2dF projectedVector = MathUtil::projectVector(testVector, targetVector);
     EXPECT_EQ(projectedVector.x() / targetVector.x(),
               projectedVector.y() / targetVector.y());
 }
 
-}  // anonymous namespace
+}  // namespace
+}  // namespace cc