Improve console message about deferring long-running timers.

components/scheduler/renderer/renderer_scheduler_impl.cc

 // Copyright 2014 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 "components/scheduler/renderer/renderer_scheduler_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 1297 matching lines @@
 
   if (!MainThreadOnly().have_reported_blocking_intervention_since_navigation) {
     {
       base::AutoLock lock(any_thread_lock_);
       if (!AnyThread().have_seen_touchstart)
         return;
     }
     MainThreadOnly().have_reported_blocking_intervention_since_navigation =
         true;
     BroadcastConsoleWarning(
-        "Deferred long-running timer task(s) to improve scrolling smoothness. "
-        "See crbug.com/574343.");
+        "Defer long-running timer task(s) to improve scrolling smoothness. "

[Sami, 2016/05/23 13:16:37]

What the message is trying to communicate is that the *browser* deferred some
tasks in favor of making scrolling smoother. The guidance for the web developer
should basically be: make sure your timer tasks take less than 50ms to run. (The
limit is about 6ms during user gestures, but I think we might want to avoid
printing the warning in that case since it is pretty spammy right now).

+        "See https://crbug.com/574343#c40");
   }
 }
 
 }  // namespace scheduler