Revert of Un-DCHECK-guard ThreadRestrictionVerifier for strings.

third_party/WebKit/Source/wtf/text/StringImpl.h

Index: third_party/WebKit/Source/wtf/text/StringImpl.h
diff --git a/third_party/WebKit/Source/wtf/text/StringImpl.h b/third_party/WebKit/Source/wtf/text/StringImpl.h
index 6a9d66c850ef61f88041733a6d782b0dc614fd39..97f2c6767bf69b877952e92764be6494d64a0b85 100644
--- a/third_party/WebKit/Source/wtf/text/StringImpl.h
+++ b/third_party/WebKit/Source/wtf/text/StringImpl.h
@@ -35,11 +35,9 @@
 #include <limits.h>
 #include <string.h>
 
-// TODO(meade): Revert this by 17 Mar 17.
-// This is for investigating crbug.com/694520
-// #if DCHECK_IS_ON()
+#if DCHECK_IS_ON()
 #include "wtf/ThreadRestrictionVerifier.h"
-// #endif
+#endif
 
 #if OS(MACOSX)
 typedef const struct __CFString* CFStringRef;
@@ -309,30 +307,24 @@
   }
 
   ALWAYS_INLINE bool hasOneRef() const {
-    // TODO(meade): Revert this by 17 Mar 17.
-    // This is for investigating crbug.com/694520
-    // #if DCHECK_IS_ON()
-    CHECK(isStatic() || m_verifier.isSafeToUse()) << asciiForDebugging();
-    // #endif
+#if DCHECK_IS_ON()
+    DCHECK(isStatic() || m_verifier.isSafeToUse()) << asciiForDebugging();
+#endif
     return m_refCount == 1;
   }
 
   ALWAYS_INLINE void ref() const {
-    // TODO(meade): Revert this by 17 Mar 17.
-    // This is for investigating crbug.com/694520
-    // #if DCHECK_IS_ON()
-    CHECK(isStatic() || m_verifier.onRef(m_refCount)) << asciiForDebugging();
-    // #endif
+#if DCHECK_IS_ON()
+    DCHECK(isStatic() || m_verifier.onRef(m_refCount)) << asciiForDebugging();
+#endif
     ++m_refCount;
   }
 
   ALWAYS_INLINE void deref() const {
-    // TODO(meade): Revert this by 17 Mar 17.
-    // This is for investigating crbug.com/694520
-    // #if DCHECK_IS_ON()
-    CHECK(isStatic() || m_verifier.onDeref(m_refCount))
+#if DCHECK_IS_ON()
+    DCHECK(isStatic() || m_verifier.onDeref(m_refCount))
         << asciiForDebugging() << " " << currentThread();
-    // #endif
+#endif
     if (!--m_refCount)
       destroyIfNotStatic();
   }
@@ -519,11 +511,9 @@
   void destroyIfNotStatic() const;
   void updateContainsOnlyASCII() const;
 
-  // TODO(meade): Revert this by 17 Mar 17.
-  // This is for investigating crbug.com/694520
-  // #if DCHECK_IS_ON()
+#if DCHECK_IS_ON()
   std::string asciiForDebugging() const;
-// #endif
+#endif
 
 #ifdef STRING_STATS
   static StringStats m_stringStats;
@@ -540,11 +530,9 @@
 #endif
 
  private:
-  // TODO(meade): Revert this by 17 Mar 17.
-  // This is for investigating crbug.com/694520
-  // #if DCHECK_IS_ON()
+#if DCHECK_IS_ON()
   mutable ThreadRestrictionVerifier m_verifier;
-  // #endif
+#endif
   mutable unsigned m_refCount;
   const unsigned m_length;
   mutable unsigned m_hash : 24;