--- a/ipc/chromium/src/chrome/common/ipc_message.h
+++ b/ipc/chromium/src/chrome/common/ipc_message.h
@@ -342,18 +342,17 @@ class Message : public Pickle {
   // Used for async messages with no parameters.
   static void Log(const Message* msg, std::wstring* l) {
   }
 
   static int HeaderSizeFromData(const char* range_start,
                                 const char* range_end) {
 #ifdef MOZ_TASK_TRACER
     return ((static_cast<unsigned int>(range_end - range_start) >= sizeof(Header)) &&
-            (reinterpret_cast<const Header*>(range_start)->flags &
-             TASKTRACER_BIT)) ?
+            (reinterpret_cast<const Header*>(range_start)->flags.IsTaskTracer())) ?
       sizeof(HeaderTaskTracer) : sizeof(Header);
 #else
     return sizeof(Header);
 #endif
   }
 
   // Figure out how big the message starting at range_start is. Returns 0 if
   // there's no enough data to determine (i.e., if [range_start, range_end) does