Allow TimelineAnalysis to work on any TimelineEventRecorder

runtime/vm/timeline.cc

Index: runtime/vm/timeline.cc
diff --git a/runtime/vm/timeline.cc b/runtime/vm/timeline.cc
index 48a67201a4a37bf0f694df7ce72283b372041e2a..d29b057d87380267231fe153c4830eb2cbccdc51 100644
--- a/runtime/vm/timeline.cc
+++ b/runtime/vm/timeline.cc
@@ -456,6 +456,11 @@ TimelineEventBlock* TimelineEventRingRecorder::GetNewBlock() {
 }
 
 
+TimelineEventBlock* TimelineEventRingRecorder::GetHeadBlock() {
+  return blocks_[0];
+}
+
+
 TimelineEventBlock* TimelineEventRingRecorder::GetNewBlockLocked() {
   if (block_cursor_ == num_blocks_) {
     block_cursor_ = 0;
@@ -569,6 +574,11 @@ TimelineEventBlock* TimelineEventEndlessRecorder::GetNewBlock() {
 }
 
 
+TimelineEventBlock* TimelineEventEndlessRecorder::GetHeadBlock() {
+  return head_;
+}
+
+
 void TimelineEventEndlessRecorder::VisitObjectPointers(
     ObjectPointerVisitor* visitor) {
   // no-op.
@@ -680,7 +690,7 @@ void TimelineEventBlock::Reset() {
 
 
 TimelineEventBlockIterator::TimelineEventBlockIterator(
-    TimelineEventEndlessRecorder* recorder)
+    TimelineEventRecorder* recorder)
     : current_(NULL),
       recorder_(recorder) {
   if (recorder_ == NULL) {
@@ -708,7 +718,7 @@ bool TimelineEventBlockIterator::Next() {
     return false;
   }
   if (current_ == NULL) {
-    current_ = recorder_->head_;
+    current_ = recorder_->GetHeadBlock();
   } else {
     current_ = current_->next();
   }