Remove more calls to HandleScope default ctor.

chrome/renderer/extensions/chrome_v8_context.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_
 #define CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 98 matching lines @@
   std::string GetContextTypeDescription();
 
   // RequestSender::Source implementation.
   virtual ChromeV8Context* GetContext() OVERRIDE;
   virtual void OnResponseReceived(const std::string& name,
                                   int request_id,
                                   bool success,
                                   const base::ListValue& response,
                                   const std::string& error) OVERRIDE;
 
+  v8::Isolate* isolate() const {
+    return isolate_;

[Jeffrey Yasskin, 2013/09/05 17:36:26]

I believe you can get this from v8_context()->GetIsolate(), so you wouldn't need
to store isolate_.

[marja, 2013/09/06 08:31:24]

v8_context_ is a ScopedPersistent, and we shouldn't [be able to] call any V8
functions (such as GetIsolate) on it. Currently we can, but it's a hack and I
should remove it asap. So the only way to call a V8 function for a
ScopedPersistent is to create a new local handle based on it, and call the
function on the local handle. But the local handle needs a HandleScope, and the
HandleScope needs an Isolate, and that's a circle. I'm breaking the circle here
by storing the isolate.

[Jeffrey Yasskin, 2013/09/06 16:10:14]

Oh, I see. Certainly a good answer for this CL. I wonder if there should be a
curated list of v8 functions you can call on Persistents, which would include
GetIsolate but not any type-specific functions. But that's a design question,
and not about the cleanup you're currently doing.

+  }
+
  private:
   // The v8 context the bindings are accessible to.
   ScopedPersistent<v8::Context> v8_context_;
 
   // The WebFrame associated with this context. This can be NULL because this
   // object can outlive is destroyed asynchronously.
   WebKit::WebFrame* web_frame_;
 
   // The extension associated with this context, or NULL if there is none. This
   // might be a hosted app in the case that this context is hosting a web URL.
   scoped_refptr<const Extension> extension_;
 
   // The type of context.
   Feature::Context context_type_;
 
   // Owns and structures the JS that is injected to set up extension bindings.
   scoped_ptr<ModuleSystem> module_system_;
 
   // Contains safe copies of builtin objects like Function.prototype.
   SafeBuiltins safe_builtins_;
 
+  v8::Isolate* isolate_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeV8Context);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_