Revert of [debugger] simplify fetching scripts for inspector.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index b421e06e7d478734307b28d5c140c51f6ed6fd15..ad41d819b7f094ddda7834f5ca57377ae8184f03 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -8946,18 +8946,13 @@
     PersistentValueVector<DebugInterface::Script>& scripts) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(v8_isolate);
   ENTER_V8(isolate);
-  {
-    i::DisallowHeapAllocation no_gc;
-    i::Script::Iterator iterator(isolate);
-    i::Script* script;
-    while ((script = iterator.Next())) {
-      if (script->type() != i::Script::TYPE_NORMAL) continue;
-      if (script->HasValidSource()) {
-        i::HandleScope handle_scope(isolate);
-        i::Handle<i::Script> script_handle(script, isolate);
-        scripts.Append(ToApiHandle<Script>(script_handle));
-      }
-    }
+  i::HandleScope handle_scope(isolate);
+  i::Handle<i::FixedArray> instances = isolate->debug()->GetLoadedScripts();
+  for (int i = 0; i < instances->length(); i++) {
+    i::Handle<i::Script> script =
+        i::Handle<i::Script>(i::Script::cast(instances->get(i)));
+    if (script->type() != i::Script::TYPE_NORMAL) continue;
+    scripts.Append(ToApiHandle<Script>(script));
   }
 }