Remove the NOTREACHED introduced by crrev.com/2323483005.

base/trace_event/trace_log.cc

 // Copyright 2015 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/trace_event/trace_log.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 #include <utility>
@@ skipping 728 matching lines @@
 
     // Can't enable tracing when Flush() is in progress.
     DCHECK(!flush_task_runner_);
 
     InternalTraceOptions new_options =
         GetInternalOptionsFromTraceConfig(trace_config);
 
     InternalTraceOptions old_options = trace_options();
 
     if (dispatching_to_observer_list_) {
-      NOTREACHED()
+      // TODO(ssid): Change to NOTREACHED after fixing crbug.com/625170.
+      DLOG(ERROR)
           << "Cannot manipulate TraceLog::Enabled state from an observer.";
       return;
     }
 
     // Clear all filters from previous tracing session. These filters are not
     // cleared at the end of tracing because some threads which hit trace event
     // when disabling, could try to use the filters.
     if (!enabled_modes_)
       g_category_group_filters.Get().clear();
 
@@ skipping 108 matching lines @@
   SetDisabledWhileLocked(modes_to_disable);
 }
 
 void TraceLog::SetDisabledWhileLocked(uint8_t modes_to_disable) {
   lock_.AssertAcquired();
 
   if (!(enabled_modes_ & modes_to_disable))
     return;
 
   if (dispatching_to_observer_list_) {
-    NOTREACHED()
+    DLOG(ERROR)

[Ilya Kulshin, 2016/10/13 23:35:07]

Add TODO here, similar to the previous call.

         << "Cannot manipulate TraceLog::Enabled state from an observer.";
     return;
   }
 
   bool is_recording_mode_disabled =
       (enabled_modes_ & RECORDING_MODE) && (modes_to_disable & RECORDING_MODE);
   enabled_modes_ &= ~modes_to_disable;
 
   if (modes_to_disable & FILTERING_MODE)
     enabled_event_filters_.clear();
@@ skipping 1082 matching lines @@
 }
 
 ScopedTraceBinaryEfficient::~ScopedTraceBinaryEfficient() {
   if (*category_group_enabled_) {
     TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_group_enabled_, name_,
                                                 event_handle_);
   }
 }
 
 }  // namespace trace_event_internal