Use WeakCells in the optimized code map rather than traversing in pause.

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index de48d3cfbaf50f86f222c478e3a578e007c976e2..d6c746d385737dd6f1b0546354756c1f85a94ca2 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -384,7 +384,7 @@ DEFINE_INT(stress_runs, 0, "number of stress runs")
 DEFINE_BOOL(lookup_sample_by_shared, true,
             "when picking a function to optimize, watch for shared function "
             "info, not JSFunction itself")
-DEFINE_BOOL(flush_optimized_code_cache, true,
+DEFINE_BOOL(flush_optimized_code_cache, false,

[Michael Starzinger, 2015/11/27 10:06:39]

I assume this is only for the try-jobs and we want to land the flag flip in a
separate CL. Correct?

[mvstanton, 2015/12/01 11:28:15]

Correct! Setting it back to true :).

             "flushes the cache of optimized code for closures on every GC")
 DEFINE_BOOL(inline_construct, true, "inline constructor calls")
 DEFINE_BOOL(inline_arguments, true, "inline functions with arguments object")