Add support to timeline for begin and end events

runtime/vm/timeline.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <cstdlib>
 
 #include "vm/atomic.h"
 #include "vm/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/lockers.h"
@@ skipping 242 matching lines @@
 
 void TimelineEvent::Duration(const char* label,
                              int64_t start_micros,
                              int64_t end_micros) {
   Init(kDuration, label);
   timestamp0_ = start_micros;
   timestamp1_ = end_micros;
 }
 
 
+void TimelineEvent::Begin(const char* label,
+                          int64_t micros) {
+  Init(kBegin, label);
+  timestamp0_ = micros;
+}
+
+
+void TimelineEvent::End(const char* label,
+                        int64_t micros) {
+  Init(kEnd, label);
+  timestamp0_ = micros;
+}
+
+
 void TimelineEvent::SetNumArguments(intptr_t length) {
   // Cannot call this twice.
   ASSERT(arguments_ == NULL);
   ASSERT(arguments_length_ == 0);
   arguments_length_ = length;
   arguments_ = reinterpret_cast<TimelineEventArgument*>(
       calloc(sizeof(TimelineEventArgument), length));
 }
 
 
@@ skipping 78 matching lines @@
   JSONObject obj(stream);
   int64_t pid = OS::ProcessId();
   int64_t tid = OSThread::ThreadIdToIntPtr(thread_);
   obj.AddProperty("name", label_);
   obj.AddProperty("cat", category_);
   obj.AddProperty64("tid", tid);
   obj.AddProperty64("pid", pid);
   obj.AddPropertyTimeMicros("ts", TimeOrigin());
 
   switch (event_type()) {
+    case kBegin: {
+      obj.AddProperty("ph", "B");
+    }
+    break;
+    case kEnd: {
+      obj.AddProperty("ph", "E");
+    }
+    break;
     case kDuration: {
       obj.AddProperty("ph", "X");
       obj.AddPropertyTimeMicros("dur", TimeDuration());
     }
     break;
     case kInstant: {
       obj.AddProperty("ph", "i");
       obj.AddProperty("s", "p");
     }
     break;
@@ skipping 880 matching lines @@
       // If an isolate was specified, skip events from other isolates.
       continue;
     }
     ASSERT(event->event_as_json() != NULL);
     result = zone->ConcatStrings(result, event->event_as_json());
   }
   return result;
 }
 
 }  // namespace dart