ScriptContextSetTest should close the main frame before finishing the test

extensions/renderer/scoped_web_frame.cc

Index: extensions/renderer/scoped_web_frame.cc
diff --git a/extensions/renderer/scoped_web_frame.cc b/extensions/renderer/scoped_web_frame.cc
new file mode 100644
index 0000000000000000000000000000000000000000..88c4098b5c33348f0773db33e396fdf0a980e353
--- /dev/null
+++ b/extensions/renderer/scoped_web_frame.cc
@@ -0,0 +1,24 @@
+// Copyright 2015 The Chromium 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 "extensions/renderer/scoped_web_frame.h"
+
+#include "third_party/WebKit/public/web/WebHeap.h"
+
+namespace extensions {
+
+ScopedWebFrame::ScopedWebFrame() : view_(nullptr), frame_(nullptr) {
+  view_ = blink::WebView::create(nullptr);
+  frame_ = blink::WebLocalFrame::create(
+      blink::WebTreeScopeType::Document, nullptr);
+  view_->setMainFrame(frame_);
+}
+
+ScopedWebFrame::~ScopedWebFrame() {
+  view_->close();
+  frame_->close();
+  blink::WebHeap::collectAllGarbageForTesting();
+}
+
+}  // namespace extensions