Avoid checking for WTFThreadData::staticData in wtfThreadData()

third_party/WebKit/Source/wtf/WTFThreadData.h

Index: third_party/WebKit/Source/wtf/WTFThreadData.h
diff --git a/third_party/WebKit/Source/wtf/WTFThreadData.h b/third_party/WebKit/Source/wtf/WTFThreadData.h
index a8228fce72e0e288153d3311b0ea25875cfe92b0..01a1a1b88ec6872c7d24dfbed26784877db49d94 100644
--- a/third_party/WebKit/Source/wtf/WTFThreadData.h
+++ b/third_party/WebKit/Source/wtf/WTFThreadData.h
@@ -55,6 +55,9 @@ class WTF_EXPORT WTFThreadData {
 
   ThreadIdentifier threadId() const { return m_threadId; }
 
+  static void initializeOnOffThread();
+  static void initializeOnMainThread();
+
 #if OS(WIN) && COMPILER(MSVC)
   static size_t threadStackSize();
 #endif
@@ -73,11 +76,37 @@ class WTF_EXPORT WTFThreadData {
   friend WTFThreadData& wtfThreadData();
 };
 
+// Special case WTFThreadData so accessors don't need to branch.
+template <>
+inline ThreadSpecific<WTFThreadData>::operator WTFThreadData*() {
+  DCHECK(isSet());
+#if defined(__GLIBC__) || OS(ANDROID) || OS(FREEBSD)
+  return static_cast<WTFThreadData*>(get());
+#else
+  if (UNLIKELY(internal::mayNotBeMainThread()))
+    return static_cast<WTFThreadData*>(get());
+  return m_mainThreadStorage;
+#endif
+}
+
+template <>
+inline void ThreadSpecific<WTFThreadData>::initializeOnOffThread() {
+  WTFThreadData* ptr = static_cast<WTFThreadData*>(Partitions::fastZeroedMalloc(
+      sizeof(WTFThreadData), WTF_HEAP_PROFILER_TYPE_NAME(WTFThreadData)));
+  set(ptr);
+  new (NotNull, ptr) WTFThreadData;
+}
+
+template <>
+inline void ThreadSpecific<WTFThreadData>::initializeOnMainThread() {
+  m_mainThreadStorage =
+      static_cast<WTFThreadData*>(Partitions::fastZeroedMalloc(
+          sizeof(WTFThreadData), WTF_HEAP_PROFILER_TYPE_NAME(WTFThreadData)));
+  set(m_mainThreadStorage);
+  new (NotNull, m_mainThreadStorage) WTFThreadData;
+}
+
 inline WTFThreadData& wtfThreadData() {
-  // WTFThreadData is used on main thread before it could possibly be used
-  // on secondary ones, so there is no need for synchronization here.
-  if (!WTFThreadData::staticData)
-    WTFThreadData::staticData = new ThreadSpecific<WTFThreadData>;
   return **WTFThreadData::staticData;
 }