Adds support for collecting statistics about code and its metadata.

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 8c330b3a1f41c466119e0399474d2e7dd9bf9608..3cfbb770931eb502248077929b0b0d7d5e0255b2 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -738,6 +738,10 @@ DEFINE_BOOL(scavenge_reclaim_unmodified_objects, true,
             "remove unmodified and unreferenced objects")
 DEFINE_INT(heap_growing_percent, 0,
            "specifies heap growing factor as (1 + heap_growing_percent/100)")
+DEFINE_BOOL(code_and_metadata_stats, false,

[rmcilroy, 2016/05/23 10:16:30]

Do we need this flag? If this is only collected when you request it is there any
reason to disable it - it shouldn't affect performance unless you call the API
should it?

[mythria, 2016/05/23 11:27:51]

Yes, it collects code statistics only when requested, so does not affect
performance. I am removing this flag. Done.

+            "Enable collection of code+metadata statistics. code+metadata "
+            "statistics are only collected when requested through an API."
+            "Use --code-stats to dump statistics related to code.")
 
 // counters.cc
 DEFINE_INT(histogram_interval, 600000,