Move Kernel strings into the VM's heap.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index f3d4e0339f8acb560d38d137713c48352edac1ca..85a2c309b3291fb26ee9ca405980fb491bd85b8d 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -9073,6 +9073,11 @@ void Script::set_compile_time_constants(const Array& value) const {
 }
 
 
+void Script::set_kernel_strings(const TypedData& strings) const {
+  StorePointer(&raw_ptr()->kernel_strings_, strings.raw());
+}
+
+
 RawGrowableObjectArray* Script::GenerateLineNumberArray() const {
   Zone* zone = Thread::Current()->zone();
   const GrowableObjectArray& info =
@@ -10150,11 +10155,8 @@ RawObject* Library::GetMetadata(const Object& obj) const {
   Object& metadata = Object::Handle();
   metadata = field.StaticValue();
   if (field.StaticValue() == Object::empty_array().raw()) {
-    kernel::TreeNode* kernel_node =
-        reinterpret_cast<kernel::TreeNode*>(field.kernel_field());
-
-    if (kernel_node != NULL) {
-      metadata = kernel::EvaluateMetadata(kernel_node);
+    if (field.kernel_field() != NULL) {
+      metadata = kernel::EvaluateMetadata(field);
     } else {
       metadata = Parser::ParseMetadata(field);
     }