Add more safe points in compiler

runtime/vm/pages.h

Index: runtime/vm/pages.h
diff --git a/runtime/vm/pages.h b/runtime/vm/pages.h
index 0cf4388cbfdbf85948a701780af447b7df8ebdff..36ab2fa4428bc274ef7f79482509a7def95df39c 100644
--- a/runtime/vm/pages.h
+++ b/runtime/vm/pages.h
@@ -324,10 +324,11 @@ class PageSpace {
   // Ids for time and data records in Heap::GCStats.
   enum {
     // Time
-    kMarkObjects = 0,
-    kResetFreeLists = 1,
-    kSweepPages = 2,
-    kSweepLargePages = 3,
+    kSafePoint = 0,
+    kMarkObjects = 1,
+    kResetFreeLists = 2,
+    kSweepPages = 3,
+    kSweepLargePages = 4,

[siva, 2017/03/23 18:05:01]

Might be a better to add the new time slot as the last entry of the times
section.

People who have been staring at verbose GC logs could have gotten used to the
first four entries being marking/resetting/sweeping etc.

[erikcorry, 2017/03/27 10:23:28]

I think it makes most sense to have them in the order they actually happen, and
safe-point waiting happens first.

But it's true that the output is hard to read. I propose padding better so that
the columns more or less line up with the header.  See new version at
https://screenshot.googleplex.com/GrM71QDzLFp vs old version at
https://screenshot.googleplex.com/CExFc3619EC

     // Data
     kGarbageRatio = 0,
     kGCTimeFraction = 1,