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

runtime/vm/timeline.h

 // 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.
 
 #ifndef VM_TIMELINE_H_
 #define VM_TIMELINE_H_
 
 #include "vm/bitfield.h"
 
 namespace dart {
@@ skipping 165 matching lines @@
   V(API, false)                                                                \
   V(Compiler, false)                                                           \
   V(Embedder, false)                                                           \
   V(GC, false)                                                                 \
   V(Isolate, false)                                                            \
 
 
 #define TIMELINE_FUNCTION_COMPILATION_DURATION(isolate, suffix, function)      \
   TimelineDurationScope tds(isolate,                                           \
                             isolate->GetCompilerStream(),                      \
-                            "Compile"#suffix);                                 \
+                            "Compile" suffix);                                 \
   if (tds.enabled()) {                                                         \
     tds.SetNumArguments(1);                                                    \
     tds.CopyArgument(                                                          \
         0,                                                                     \
         "function",                                                            \
         const_cast<char*>(function.QualifiedUserVisibleNameCString()));        \
   }
 
 class TimelineDurationScope : public StackResource {
  public:
@@ skipping 207 matching lines @@
   TimelineEventBlock* GetNewBlockLocked();
   void PrintJSONEvents(JSONArray* array) const;
 
   Mutex lock_;
   TimelineEventBlock* head_;
 };
 
 }  // namespace dart
 
 #endif  // VM_TIMELINE_H_