Use NESTABLE_ASYNC APIs to get NetLog data into Tracing

base/debug/trace_event.h

Index: base/debug/trace_event.h
diff --git a/base/debug/trace_event.h b/base/debug/trace_event.h
index f9dc1c94d6d65b885772a4b1bf3b16005c58c2e9..565812c1107cfddb0c46a484c2871e98065fe0f0 100644
--- a/base/debug/trace_event.h
+++ b/base/debug/trace_event.h
@@ -634,6 +634,34 @@
         static_cast<int>(base::PlatformThread::CurrentId()), \
         timestamp, TRACE_EVENT_FLAG_NONE)
 
+
+// Records a single NET_LOG_BEGIN event called "name" immediately, with 1
+// associated argument. If the category is not enabled, then this
+// does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+// - |id| is used to match the NET_LOG_BEGIN event with the NET_LOG_END event.
+//   Events are considered to match if their category_group, name and id values
+//   all match. |id| must either be a pointer or an integer value up to 64 bits.
+//   If it's a pointer, the bits will be xored with a hash of the process ID so
+//   that the same pointer on two different processes will not collide.
+// NET_LOG_ events are supposed to be used for logging NetLog events only.
+
+#define TRACE_EVENT_NET_LOG_BEGIN(category_group, name, id, arg1_name, \
+        arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NET_LOG_BEGIN, \
+        category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+// Records a single NET_LOG_END event for "name" immediately. If the category
+// is not enabled, then this does nothing.
+#define TRACE_EVENT_NET_LOG_END(category_group, name, id, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NET_LOG_END, \
+        category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+// Records a single NET_LOG_INSTANT event for "name" immediately.
+// If the category is not enabled, then this does nothing.
+#define TRACE_EVENT_NET_LOG_INSTANT(category_group, name, id, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NET_LOG_INSTANT, \
+        category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+
 // Records a single FLOW_BEGIN event called "name" immediately, with 0, 1 or 2
 // associated arguments. If the category is not enabled, then this
 // does nothing.
@@ -972,6 +1000,9 @@ TRACE_EVENT_API_CLASS_EXPORT extern \
 #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_NET_LOG_BEGIN ('b')
+#define TRACE_EVENT_PHASE_NET_LOG_END ('e')
+#define TRACE_EVENT_PHASE_NET_LOG_INSTANT ('i')
 
 // Flags for changing the behavior of TRACE_EVENT_API_ADD_TRACE_EVENT.
 #define TRACE_EVENT_FLAG_NONE         (static_cast<unsigned char>(0))