[Tracing Clock Sync] Implement clock sync in Chrome

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)
 
+// 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())
+
 // Macros to track the life time and value of arbitrary client objects.
 // See also TraceTrackableObject.
 #define TRACE_EVENT_OBJECT_CREATED_WITH_ID(category_group, name, id) \
   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                  \
       TRACE_EVENT_PHASE_CREATE_OBJECT, category_group, name,         \
       TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE)
 
 #define TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(category_group, name, id, \
                                             snapshot)                 \
   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                   \
@@ skipping 67 matching lines @@
 #define TRACE_EVENT_PHASE_FLOW_STEP ('t')
 #define TRACE_EVENT_PHASE_FLOW_END ('f')
 #define TRACE_EVENT_PHASE_METADATA ('M')
 #define TRACE_EVENT_PHASE_COUNTER ('C')
 #define TRACE_EVENT_PHASE_SAMPLE ('P')
 #define TRACE_EVENT_PHASE_CREATE_OBJECT ('N')
 #define TRACE_EVENT_PHASE_SNAPSHOT_OBJECT ('O')
 #define TRACE_EVENT_PHASE_DELETE_OBJECT ('D')
 #define TRACE_EVENT_PHASE_MEMORY_DUMP ('v')
 #define TRACE_EVENT_PHASE_MARK ('R')
+#define TRACE_EVENT_PHASE_CLOCK_SYNC ('c')
 
 // Flags for changing the behavior of TRACE_EVENT_API_ADD_TRACE_EVENT.
 #define TRACE_EVENT_FLAG_NONE (static_cast<unsigned int>(0))
 #define TRACE_EVENT_FLAG_COPY (static_cast<unsigned int>(1 << 0))
 #define TRACE_EVENT_FLAG_HAS_ID (static_cast<unsigned int>(1 << 1))
 #define TRACE_EVENT_FLAG_MANGLE_ID (static_cast<unsigned int>(1 << 2))
 #define TRACE_EVENT_FLAG_SCOPE_OFFSET (static_cast<unsigned int>(1 << 3))
 #define TRACE_EVENT_FLAG_SCOPE_EXTRA (static_cast<unsigned int>(1 << 4))
 #define TRACE_EVENT_FLAG_EXPLICIT_TIMESTAMP (static_cast<unsigned int>(1 << 5))
 #define TRACE_EVENT_FLAG_ASYNC_TTS (static_cast<unsigned int>(1 << 6))
@@ skipping 19 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')