Change sampler code events phase from instant to meta.

base/trace_event/common/trace_event_common.h

 // 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.
 
 // This header file defines the set of trace_event macros without specifying
 // how the events actually get collected and stored. If you need to expose trace
 // events to some other universe, you can copy-and-paste this file as well as
 // trace_event.h, modifying the macros contained there as necessary for the
 // target platform. The end result is that multiple libraries can funnel events
 // through to a shared trace event collector.
@@ skipping 908 matching lines @@
                                    arg1_val)                                   \
   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
                                    name, id, TRACE_EVENT_FLAG_COPY, arg1_name, \
                                    arg1_val)
 #define TRACE_EVENT_COPY_FLOW_END2(category_group, name, id, arg1_name,        \
                                    arg1_val, arg2_name, arg2_val)              \
   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
                                    name, id, TRACE_EVENT_FLAG_COPY, arg1_name, \
                                    arg1_val, arg2_name, arg2_val)
 
+// TRACE_EVENT_METADATA* events are information related to other
+// injected events, not events in their own right.
+#define TRACE_EVENT_METADATA1(category_group, name, arg1_name, arg1_val) \
+  INTERNAL_TRACE_EVENT_METADATA_ADD(category_group, name, arg1_name, arg1_val)
+
 // Records a clock sync event.
 #define TRACE_EVENT_CLOCK_SYNC_RECEIVER(sync_id)                               \
   INTERNAL_TRACE_EVENT_ADD(                                                    \
       TRACE_EVENT_PHASE_CLOCK_SYNC, "__metadata", "clock_sync",                \
       TRACE_EVENT_FLAG_NONE, "sync_id", sync_id)
 #define TRACE_EVENT_CLOCK_SYNC_ISSUER(sync_id, issue_ts, issue_end_ts)         \
   INTERNAL_TRACE_EVENT_ADD_WITH_TIMESTAMP(                                     \
       TRACE_EVENT_PHASE_CLOCK_SYNC, "__metadata", "clock_sync",                \
       issue_end_ts.ToInternalValue(), TRACE_EVENT_FLAG_NONE,                   \
       "sync_id", sync_id, "issue_ts", issue_ts.ToInternalValue())
@@ skipping 135 matching lines @@
 
 // Enum reflecting the scope of an INSTANT event. Must fit within
 // TRACE_EVENT_FLAG_SCOPE_MASK.
 #define TRACE_EVENT_SCOPE_GLOBAL (static_cast<unsigned char>(0 << 3))
 #define TRACE_EVENT_SCOPE_PROCESS (static_cast<unsigned char>(1 << 3))
 #define TRACE_EVENT_SCOPE_THREAD (static_cast<unsigned char>(2 << 3))
 
 #define TRACE_EVENT_SCOPE_NAME_GLOBAL ('g')
 #define TRACE_EVENT_SCOPE_NAME_PROCESS ('p')
 #define TRACE_EVENT_SCOPE_NAME_THREAD ('t')