Reland "Fixed a couple of failing DCHECK(has_pending_exception())."

src/runtime/runtime-debug.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/debug.h"
@@ skipping 2730 matching lines @@
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugGetLoadedScripts) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 0);
 
   Handle<FixedArray> instances;
   {
     DebugScope debug_scope(isolate->debug());
+    if (debug_scope.failed()) {
+      DCHECK(isolate->has_pending_exception());
+      return isolate->heap()->exception();
+    }
     // Fill the script objects.
     instances = isolate->debug()->GetLoadedScripts();
   }
 
   // Convert the script objects to proper JS objects.
   for (int i = 0; i < instances->length(); i++) {
     Handle<Script> script = Handle<Script>(Script::cast(instances->get(i)));
     // Get the script wrapper in a local handle before calling GetScriptWrapper,
     // because using
     //   instances->set(i, *GetScriptWrapper(script))
@@ skipping 450 matching lines @@
   return Smi::FromInt(isolate->debug()->is_active());
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8