Remove WTF::DoubleBufferedDeque.

Source/wtf/DoubleBufferedDequeTest.cpp

-// Copyright 2014 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 "wtf/DoubleBufferedDeque.h"
-
-#include <gtest/gtest.h>
-
-namespace {
-
-typedef testing::Test DoubleBufferedDequeTest;
-
-TEST(DoubleBufferedDequeTest, TestIsEmpty)
-{
-    DoubleBufferedDeque<int> queue;
-
-    EXPECT_TRUE(queue.isEmpty());
-    queue.append(1);
-    EXPECT_FALSE(queue.isEmpty());
-}
-
-TEST(DoubleBufferedDequeTest, TestIsEmptyAfterSwapBuffers)
-{
-    DoubleBufferedDeque<int> queue;
-    queue.append(1);
-
-    queue.swapBuffers();
-    EXPECT_TRUE(queue.isEmpty());
-}
-
-TEST(DoubleBufferedDequeTest, TestDoubleBuffering)
-{
-    DoubleBufferedDeque<int> queue;
-    queue.append(1);
-    queue.append(10);
-    queue.append(100);
-
-    {
-        Deque<int>& deque = queue.swapBuffers();
-        EXPECT_EQ(1, deque.takeFirst());
-        EXPECT_EQ(10, deque.takeFirst());
-        EXPECT_EQ(100, deque.takeFirst());
-    }
-    queue.append(2);
-
-    EXPECT_EQ(2, queue.swapBuffers().takeFirst());
-    queue.append(3);
-
-    EXPECT_EQ(3, queue.swapBuffers().takeFirst());
-}
-
-} // namespace