Invoke trace callback even when trace buffer is full

base/debug/trace_event_impl.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/debug/trace_event_impl.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/leak_annotations.h"
@@ skipping 982 matching lines @@
 #if defined(OS_ANDROID)
   SendToATrace(phase, GetCategoryGroupName(category_group_enabled), name, id,
                num_args, arg_names, arg_types, arg_values, flags);
 #endif
 
   TimeTicks now = timestamp - time_offset_;
   EventCallback event_callback_copy;
 
   NotificationHelper notifier(this);
 
-  {
+  do {
     AutoLock lock(lock_);
     if (*category_group_enabled != CATEGORY_ENABLED)
       return;
+
+    event_callback_copy = event_callback_;
     if (logged_events_->IsFull())
-      return;
+      break;
 
     const char* new_name = ThreadIdNameManager::GetInstance()->
         GetName(thread_id);
     // Check if the thread name has been set or changed since the previous
     // call (if any), but don't bother if the new name is empty. Note this will
     // not detect a thread name change within the same char* buffer address: we
     // favor common case performance over corner case correctness.
     if (new_name != g_current_thread_name.Get().Get() &&
         new_name && *new_name) {
       g_current_thread_name.Get().Set(new_name);
@@ skipping 21 matching lines @@
     logged_events_->AddEvent(TraceEvent(thread_id,
         now, phase, category_group_enabled, name, id,
         num_args, arg_names, arg_types, arg_values,
         flags));
 
     if (logged_events_->IsFull())
       notifier.AddNotificationWhileLocked(TRACE_BUFFER_FULL);
 
     if (watch_category_ == category_group_enabled && watch_event_name_ == name)
       notifier.AddNotificationWhileLocked(EVENT_WATCH_NOTIFICATION);
-
-    event_callback_copy = event_callback_;
-  }  // release lock
+  } while (0); // release lock
 
   notifier.SendNotificationIfAny();
   if (event_callback_copy != NULL) {
     event_callback_copy(phase, category_group_enabled, name, id,
         num_args, arg_names, arg_types, arg_values,
         flags);
   }
 }
 
 void TraceLog::AddTraceEventEtw(char phase,
@@ skipping 280 matching lines @@
         0,                       // num_args
         NULL,                    // arg_names
         NULL,                    // arg_types
         NULL,                    // arg_values
         TRACE_EVENT_FLAG_NONE);  // flags
   }
 }
 
 }  // namespace trace_event_internal