Add timeline stream control and trace retrieval to the dart embedder api.

runtime/vm/dart_api_impl_test.cc

 // Copyright (c) 2012, 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 "bin/builtin.h"
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 #include "include/dart_tools_api.h"
 #include "platform/assert.h"
@@ skipping 9260 matching lines @@
 
   Dart_TimelineAsyncEnd("testAsyncEvent", async_id);
 
   // Check that it is in the output.
   TimelineEventRecorder* recorder = isolate->timeline_event_recorder();
   JSONStream js;
   recorder->PrintJSON(&js);
   EXPECT_SUBSTRING("testAsyncEvent", js.ToCString());
 }
 
+
+TEST_CASE(Timeline_Dart_TimelineGetTrace) {
+  const char* kScriptChars =
+    "foo() => 'a';\n"
+    "main() => foo();\n";
+
+  Dart_Handle lib =
+      TestCase::LoadTestScript(kScriptChars, NULL);
+
+  const char* buffer = NULL;
+  intptr_t buffer_length = 0;
+  bool success = false;
+
+  // Enable recording of all streams.
+  Dart_TimelineSetRecordedStreams(DART_TIMELINE_STREAM_ALL);
+
+  // Invoke main, which will be compiled resulting in a compiler event in
+  // the timeline.
+  Dart_Handle result = Dart_Invoke(lib,
+                                   NewString("main"),
+                                   0,
+                                   NULL);
+  EXPECT_VALID(result);
+
+  // Grab the trace.
+  success = Dart_TimelineGetTrace(&buffer, &buffer_length);
+  EXPECT(success);
+  EXPECT(buffer_length > 0);
+  EXPECT(buffer != NULL);
+  // Heartbeat test.
+  EXPECT_SUBSTRING("\"cat\":\"Compiler\"", buffer);
+  EXPECT_SUBSTRING("\"name\":\"CompileFunction\"", buffer);
+  EXPECT_SUBSTRING("\"function\":\"main\"", buffer);
+}
+
 }  // namespace dart