Replace ENABLE(ASSERT) with DCHECK_IS_ON().

third_party/WebKit/Source/core/workers/WorkerThread.cpp

Index: third_party/WebKit/Source/core/workers/WorkerThread.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerThread.cpp b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
index 6b9fdb892abd266bb2abf9029b819d9dcde32864..56fd9be0ed358a3d1f3fa65a4de8828ed0f906f7 100644
--- a/third_party/WebKit/Source/core/workers/WorkerThread.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
@@ -636,8 +636,8 @@ void WorkerThread::setExitCode(const MutexLocker& lock, ExitCode exitCode) {
 }
 
 bool WorkerThread::isThreadStateMutexLocked(const MutexLocker& /* unused */) {
-#if ENABLE(ASSERT)
-  // Mutex::locked() is available only if ENABLE(ASSERT) is true.
+#if DCHECK_IS_ON()
+  // Mutex::locked() is available only if DCHECK_IS_ON() is true.
   return m_threadStateMutex.locked();
 #else
   // Otherwise, believe the given MutexLocker holds |m_threadStateMutex|.