Add support for writing unit tests for Mojo-backed apps/extensions APIs.

extensions/renderer/script_context.cc

 // Copyright 2014 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/script_context.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ skipping 103 matching lines @@
   v8::HandleScope handle_scope(isolate());
   v8::Context::Scope context_scope(v8_context());
 
   v8::Handle<v8::Value> argv[] = {
       v8::String::NewFromUtf8(isolate(), event_name), args};
   module_system_->CallModuleMethod(
       kEventBindings, "dispatchEvent", arraysize(argv), argv);
 }
 
 void ScriptContext::DispatchOnUnloadEvent() {
+  v8::HandleScope handle_scope(isolate());
+  v8::Context::Scope context_scope(v8_context());
   module_system_->CallModuleMethod("unload_event", "dispatch");
 }
 
 std::string ScriptContext::GetContextTypeDescription() {
   switch (context_type_) {
     case Feature::UNSPECIFIED_CONTEXT:
       return "UNSPECIFIED";
     case Feature::BLESSED_EXTENSION_CONTEXT:
       return "BLESSED_EXTENSION";
     case Feature::UNBLESSED_EXTENSION_CONTEXT:
@@ skipping 103 matching lines @@
                                           v8::Handle<v8::Value> argv[]) {
   return CallFunction(function, argc, argv);
 }
 
 gin::ContextHolder* ScriptContext::GetContextHolder() {
   v8::HandleScope handle_scope(isolate());
   return gin::PerContextData::From(v8_context())->context_holder();
 }
 
 }  // namespace extensions