Grow heap slower if --optimize-for-size flag is on.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 8c507d48978bf5aebd6a11eb4e5ebc1e81e3b3b3..56a7941d261b0b0debb42b37f60c42639ca1f167 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -5598,7 +5598,8 @@ void Heap::SetOldGenerationAllocationLimit(intptr_t old_gen_size,
 
   // We set the old generation growing factor to 2 to grow the heap slower on
   // memory-constrained devices.
-  if (max_old_generation_size_ <= kMaxOldSpaceSizeMediumMemoryDevice) {
+  if (max_old_generation_size_ <= kMaxOldSpaceSizeMediumMemoryDevice ||
+      FLAG_optimize_for_size) {
     factor = Min(factor, kMaxHeapGrowingFactorMemoryConstrained);
   }