Refactor some Timeline interfaces to be simpler and support streaming

runtime/vm/deopt_instructions.cc

Index: runtime/vm/deopt_instructions.cc
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index 211cb78e6ea475c094424bc0880754c07371dd78..326076038cdcf46b8ea4850aaf0e691ef077196d 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -100,9 +100,9 @@ DeoptContext::DeoptContext(const StackFrame* frame,
     Isolate* isolate = Isolate::Current();
     TimelineStream* compiler_stream = isolate->GetCompilerStream();
     ASSERT(compiler_stream != NULL);
-    timeline_event_ = compiler_stream->RecordEvent();
+    timeline_event_ = compiler_stream->StartEvent();
     if (timeline_event_ != NULL) {
-      timeline_event_->DurationBegin(compiler_stream, "Deoptimize");
+      timeline_event_->DurationBegin("Deoptimize");
       timeline_event_->SetNumArguments(3);
     }
   }
@@ -158,6 +158,7 @@ DeoptContext::~DeoptContext() {
         "%d",
         function.deoptimization_counter());
     timeline_event_->DurationEnd();
+    timeline_event_->Complete();
   }
 }