[debugger] simplify fetching scripts for inspector.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index ad41d819b7f094ddda7834f5ca57377ae8184f03..04f17656f7fade2991fc56959480884b361c6144 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -8946,13 +8946,19 @@ void DebugInterface::GetLoadedScripts(
     PersistentValueVector<DebugInterface::Script>& scripts) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(v8_isolate);
   ENTER_V8(isolate);
-  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));
+  i::Factory* factory = isolate->factory();
+  {
+    i::DisallowHeapAllocation no_gc;

[kozy, 2016/11/03 01:23:36]

I'm just wondering. What this disallow heap allocation scope actually do? Will
it crash on heap allocation, or heap allocation will return something like empty
handler?

And I noticed that i::WeakFixedArray inside of i::Script::Iterator contains
i::DissalowHeapAllocation but only in debug build.

[Yang, 2016/11/03 07:47:09]

The DisallowHeapAllocation scope causes assertion failure in debug mode if
allocation happens inside the scope.

+    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));
+      }
+    }
   }
 }