Move files in wtf/ to platform/wtf/ (Part 7).

third_party/WebKit/Source/wtf/ThreadRestrictionVerifier.h

Index: third_party/WebKit/Source/wtf/ThreadRestrictionVerifier.h
diff --git a/third_party/WebKit/Source/wtf/ThreadRestrictionVerifier.h b/third_party/WebKit/Source/wtf/ThreadRestrictionVerifier.h
index 5af787c33be67398929fa4470e76aed9070c09f7..fb22bea42c227db354dd675ef1881b943fa6088d 100644
--- a/third_party/WebKit/Source/wtf/ThreadRestrictionVerifier.h
+++ b/third_party/WebKit/Source/wtf/ThreadRestrictionVerifier.h
@@ -1,108 +1,9 @@
-/*
- * Copyright (C) 2011 Google Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
+// Copyright 2017 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 ThreadRestrictionVerifier_h
-#define ThreadRestrictionVerifier_h
+#include "platform/wtf/ThreadRestrictionVerifier.h"
 
-#include "wtf/Assertions.h"
-
-#if DCHECK_IS_ON()
-
-#include "wtf/Threading.h"
-
-namespace WTF {
-
-// Verifies that a class is used in a way that respects its lack of
-// thread-safety.  The default mode is to verify that the object will only be
-// used on a single thread. The thread gets captured when setShared(true) is
-// called.  The mode may be changed by calling useMutexMode (or
-// turnOffVerification).
-class ThreadRestrictionVerifier {
- public:
-  ThreadRestrictionVerifier() : m_shared(false), m_owningThread(0) {}
-
-  // Call onRef() before refCount is incremented in ref(). Returns whether the
-  // ref() is safe.
-  template <typename COUNTERTYPE>
-  bool onRef(COUNTERTYPE refCount) {
-    // Start thread verification as soon as the ref count gets to 2. This
-    // heuristic reflects the fact that items are often created on one
-    // thread and then given to another thread to be used.
-    // FIXME: Make this restriction tigher. Especially as we move to more
-    // common methods for sharing items across threads like
-    // CrossThreadCopier.h
-    // We should be able to add a "detachFromThread" method to make this
-    // explicit.
-    if (refCount == 1)
-      setShared(true);
-    return isSafeToUse();
-  }
-
-  // Call onDeref() before refCount is decremented in deref(). Returns whether
-  // the deref() is safe.
-  template <typename COUNTERTYPE>
-  bool onDeref(COUNTERTYPE refCount) {
-    bool safe = isSafeToUse();
-    // Stop thread verification when the ref goes to 1 because it
-    // is safe to be passed to another thread at this point.
-    if (refCount == 2)
-      setShared(false);
-    return safe;
-  }
-
-  // Is it OK to use the object at this moment on the current thread?
-  bool isSafeToUse() const {
-    return !m_shared || m_owningThread == currentThread();
-  }
-
- private:
-  // Indicates that the object may (or may not) be owned by more than one place.
-  void setShared(bool shared) {
-    bool previouslyShared = m_shared;
-    m_shared = shared;
-
-    if (!m_shared)
-      return;
-
-    DCHECK_NE(shared, previouslyShared);
-    // Capture the current thread to verify that subsequent ref/deref happen on
-    // this thread.
-    m_owningThread = currentThread();
-  }
-
-  bool m_shared;
-
-  ThreadIdentifier m_owningThread;
-};
-
-}  // namespace WTF
-
-#endif  // DCHECK_IS_ON()
-#endif  // ThreadRestrictionVerifier_h
+// The contents of this header was moved to platform/wtf as part of
+// WTF migration project. See the following post for details:
+// https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gYCAAJ