Add TaskTraits hints to AssertIO/WaitAllowed messages.

base/threading/thread_restrictions.cc

 // Copyright (c) 2012 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.
 
 #include "base/threading/thread_restrictions.h"
 
 #if DCHECK_IS_ON()
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ skipping 17 matching lines @@
 // static
 bool ThreadRestrictions::SetIOAllowed(bool allowed) {
   bool previous_disallowed = g_io_disallowed.Get().Get();
   g_io_disallowed.Get().Set(!allowed);
   return !previous_disallowed;
 }
 
 // static
 void ThreadRestrictions::AssertIOAllowed() {
   if (g_io_disallowed.Get().Get()) {
-    NOTREACHED() <<
-        "Function marked as IO-only was called from a thread that "
-        "disallows IO!  If this thread really should be allowed to "
-        "make IO calls, adjust the call to "
-        "base::ThreadRestrictions::SetIOAllowed() in this thread's "
-        "startup.";
+    NOTREACHED() << "Function marked as IO-only was called from a thread that "
+                    "disallows IO!  If this thread really should be allowed to "
+                    "make IO calls, adjust the call to "
+                    "base::ThreadRestrictions::SetIOAllowed() in this thread's "
+                    "startup.  If this task is running inside the "
+                    "TaskScheduler, the TaskRunner used to post it needs to "
+                    "have MayBlock() in its TaskTraits.";
   }
 }
 
 // static
 bool ThreadRestrictions::SetSingletonAllowed(bool allowed) {
   bool previous_disallowed = g_singleton_disallowed.Get().Get();
   g_singleton_disallowed.Get().Set(!allowed);
   return !previous_disallowed;
 }
 
@@ skipping 13 matching lines @@
 
 // static
 void ThreadRestrictions::DisallowWaiting() {
   g_wait_disallowed.Get().Set(true);
 }
 
 // static
 void ThreadRestrictions::AssertWaitAllowed() {
   if (g_wait_disallowed.Get().Get()) {
     NOTREACHED() << "Waiting is not allowed to be used on this thread to "
-                 << "prevent jank and deadlock.";
+                 << "prevent jank and deadlock.  If this task is running "
+                    "inside the TaskScheduler, the TaskRunner used to post it "
+                    "needs to have WithBaseSyncPrimitives() in its TaskTraits.";
   }
 }
 
 bool ThreadRestrictions::SetWaitAllowed(bool allowed) {
   bool previous_disallowed = g_wait_disallowed.Get().Get();
   g_wait_disallowed.Get().Set(!allowed);
   return !previous_disallowed;
 }
 
 }  // namespace base
 
 #endif  // DCHECK_IS_ON()