Add -optimize-for-size flag to optimize for memory size

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index e734c7d3c6429bce47455261a1bb36cec37dcafd..4083ec1e093262e3c6e7fd77612b91d3c99200ff 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -222,6 +222,11 @@ DEFINE_implication(track_heap_object_fields, track_fields)
 DEFINE_implication(track_computed_fields, track_fields)
 DEFINE_bool(smi_binop, true, "support smi representation in binary operations")
 
+// Flags for optimization types.
+DEFINE_bool(optimize_for_size, false,
+            "Enables optimizations which favor memory size over execution "
+            "speed.")
+
 // Flags for data representation optimizations
 DEFINE_bool(unbox_double_arrays, true, "automatically unbox arrays of doubles")
 DEFINE_bool(string_slices, true, "use string slices")
@@ -594,9 +599,6 @@ DEFINE_int(hash_seed,
            0,
            "Fixed seed to use to hash property keys (0 means random)"
            "(with snapshots this option cannot override the baked-in seed)")
-DEFINE_maybe_bool(force_memory_constrained,
-           "force (if true) or prevent (if false) the runtime from treating "
-           "the device as being memory constrained.")
 
 // v8.cc
 DEFINE_bool(preemption, false,