Add a ResourceConstraint for the embedder to specify that V8 is running on a memory constrained dev…

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 741c4c02ffb17cf409f16a4067e3fd560bc5e2b2..38c1736b209a67c73cb9f257967978f771ae9b0c 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -1128,6 +1128,13 @@ class Isolate {
   // Given an address occupied by a live code object, return that object.
   Object* FindCodeObject(Address a);
 
+  bool is_memory_constrained() const {
+    return is_memory_constrained_;
+  }
+  void set_is_memory_constrained(bool value) {
+    is_memory_constrained_ = value;
+  }
+
  private:
   Isolate();
 
@@ -1304,6 +1311,7 @@ class Isolate {
   DateCache* date_cache_;
   unibrow::Mapping<unibrow::Ecma262Canonicalize> interp_canonicalize_mapping_;
   CodeStubInterfaceDescriptor* code_stub_interface_descriptors_;
+  bool is_memory_constrained_;
 
   // True if fatal error has been signaled for this isolate.
   bool has_fatal_error_;