Add a flag to specify fixed heap growing factor to be used in tests.

BUG=chromium:565306
LOG=NO

Review URL: https://codereview.chromium.org/1497743003

Cr-Commit-Position: refs/heads/master@{#32603}

src/flag-definitions.h

@@ -695,6 +695,8 @@ DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
 DEFINE_BOOL(memory_reducer, true, "use memory reducer")
 DEFINE_BOOL(scavenge_reclaim_unmodified_objects, false,
             "remove unmodified and unreferenced objects")
+DEFINE_INT(heap_growing_percent, 0,
+           "specifies heap growing factor as (1 + heap_growing_percent/100)")
 
 // counters.cc
 DEFINE_INT(histogram_interval, 600000,

src/heap/heap.cc

@@ -4911,6 +4911,10 @@ void Heap::SetOldGenerationAllocationLimit(intptr_t old_gen_size,
     factor = kMinHeapGrowingFactor;
   }
 
+  if (FLAG_heap_growing_percent > 0) {
+    factor = 1.0 + FLAG_heap_growing_percent / 100.0;
+  }
+
   old_generation_allocation_limit_ =
       CalculateOldGenerationAllocationLimit(factor, old_gen_size);