Move Mailbox from cc to gpu, and its traits to gpu/ipc

cc/texture_layer_unittest.cc

Index: cc/texture_layer_unittest.cc
diff --git a/cc/texture_layer_unittest.cc b/cc/texture_layer_unittest.cc
index 16487d575f4f0dc874215914943c32d4d1750538..6aaf45957c571b774a07cf83cdd3984417ee99c0 100644
--- a/cc/texture_layer_unittest.cc
+++ b/cc/texture_layer_unittest.cc
@@ -207,11 +207,11 @@ struct CommonMailboxObjects {
         m_releaseMailbox2 = base::Bind(&MockMailboxCallback::Release,
                                        base::Unretained(&m_mockCallback),
                                        m_mailboxName2);
-        Mailbox m1;
-        m1.setName(reinterpret_cast<const int8*>(m_mailboxName1.data()));
+        gpu::Mailbox m1;
+        m1.SetName(reinterpret_cast<const int8*>(m_mailboxName1.data()));
         m_mailbox1 = TextureMailbox(m1, m_releaseMailbox1, m_syncPoint1);
-        Mailbox m2;
-        m2.setName(reinterpret_cast<const int8*>(m_mailboxName2.data()));
+        gpu::Mailbox m2;
+        m2.SetName(reinterpret_cast<const int8*>(m_mailboxName2.data()));
         m_mailbox2 = TextureMailbox(m2, m_releaseMailbox2, m_syncPoint2);
     }