cc: Remove forbidden using namespace directives.

cc/heads_up_display_unittest.cc

Index: cc/heads_up_display_unittest.cc
diff --git a/cc/heads_up_display_unittest.cc b/cc/heads_up_display_unittest.cc
index f93adaefab3b56641430b361d74af8d2b8d7ff1f..81e7b2753dc2cc896a5cda569dc30646ca763e59 100644
--- a/cc/heads_up_display_unittest.cc
+++ b/cc/heads_up_display_unittest.cc
@@ -9,9 +9,9 @@
 #include "cc/layer_tree_host.h"
 #include "cc/test/layer_tree_test_common.h"
 
-using namespace cc;
 using namespace WebKitTests;
 
+namespace cc {
 namespace {
 
 class HeadsUpDisplayTest : public ThreadedTest {
@@ -110,4 +110,5 @@ TEST_F(HudWithRootLayerChange, runMultiThread)
     runTest(true);
 }
 
-}  // anonymous namespace
+}  // namespace
+}  // namespace cc