[tracing] Add trace events filtering predicate for heap profiler

base/trace_event/trace_event.h

 // 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.
 
 #ifndef BASE_TRACE_EVENT_TRACE_EVENT_H_
 #define BASE_TRACE_EVENT_TRACE_EVENT_H_
 
 // This header file defines implementation details of how the trace macros in
 // trace_event_common.h collect and store trace events. Anything not
 // implementation-specific should go in trace_event_common.h instead of here.
@@ skipping 58 matching lines @@
     trace_event_internal::TraceEventSamplingStateScope<bucket_number>   \
         traceEventSamplingScope(category "\0" name);
 
 #define TRACE_EVENT_API_CURRENT_THREAD_ID \
   static_cast<int>(base::PlatformThread::CurrentId())
 
 #define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() \
   UNLIKELY(*INTERNAL_TRACE_EVENT_UID(category_group_enabled) &           \
            (base::trace_event::TraceLog::ENABLED_FOR_RECORDING |         \
             base::trace_event::TraceLog::ENABLED_FOR_EVENT_CALLBACK |    \
-            base::trace_event::TraceLog::ENABLED_FOR_ETW_EXPORT))
+            base::trace_event::TraceLog::ENABLED_FOR_ETW_EXPORT |        \
+            base::trace_event::TraceLog::ENABLED_FOR_FILTERING))

[ssid, 2016/08/18 18:03:12]

As far as I can see there is no harm in adding this line here since there is a
check in AddTraceEventWithThreadIdAndTimestamp and metadata events aren't
enabled for filtering.
I cannot change the name of this macro since it is being used by
trace_event_common.h

 
 #define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_FILTERING_MODE( \
     category_group_enabled)                                             \
   UNLIKELY(category_group_enabled&                                      \
                base::trace_event::TraceLog::ENABLED_FOR_FILTERING)
 
 ////////////////////////////////////////////////////////////////////////////////
 // Implementation specific tracing API definitions.
 
 // Get a pointer to the enabled state of the given trace category. Only
@@ skipping 1037 matching lines @@
   const char* name_;
   IDType id_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceScopedTrackableObject);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_H_