Make the v8 Isolate used in the proxy resolver explicit.

chrome/browser/io_thread.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_BROWSER_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 46 matching lines @@
 class URLRequestContext;
 class URLRequestContextGetter;
 class URLRequestThrottlerManager;
 class URLSecurityManager;
 }  // namespace net
 
 namespace policy {
 class PolicyService;
 }  // namespace policy
 
+namespace v8 {
+class Isolate;
+}  // namespace v8
+
 // Contains state associated with, initialized and cleaned up on, and
 // primarily used on, the IO thread.
 //
 // If you are looking to interact with the IO thread (e.g. post tasks
 // to it or check if it is the current thread), see
 // content::BrowserThread.
 class IOThread : public content::BrowserThreadDelegate {
  public:
   struct Globals {
     template <typename T>
@@ skipping 81 matching lines @@
     Optional<bool> enable_spdy_ip_pooling;
     Optional<bool> enable_spdy_credential_frames;
     Optional<bool> enable_spdy_compression;
     Optional<bool> enable_spdy_ping_based_connection_checking;
     Optional<net::NextProto> spdy_default_protocol;
     Optional<uint16> origin_port_to_force_quic_on;
     // NetErrorTabHelper uses |dns_probe_service| to send DNS probes when a
     // main frame load fails with a DNS error in order to provide more useful
     // information to the renderer so it can show a more specific error page.
     scoped_ptr<chrome_browser_net::DnsProbeService> dns_probe_service;
+    // The v8 default Isolate for the main thread.

[jochen (gone - plz use gerrit), 2013/01/18 13:29:07]

the comment is a bit misleading, since we'll use it on the IO thread.

isn't it also the case that it's only safe to use this isolate from one thread
at a time, so whoever uses it needs to make sure to lock v8 user a V8::Locker?

[Sven Panne, 2013/01/18 14:27:33]

OK, it is v8's default Isolate, retrieved *from* the main thread. I'll change
that...
It's a bit the other way round: We actually need the Isolate in the (Un)Locker
constructor to allow any usage of it in the current thread.

V8's API is a bit ugly regarding this: Compared to Java's JNI, we don't really
distinguish between JavaVM and JNIEnv, and we mix Attach/DetachCurrentThread
with the actual locking.

Isolates have been an afterthought and cleaning all this mess up is a long,
ongoing task, where this current CL is a tiny step...

+    v8::Isolate* v8_default_isolate;
   };
 
   // |net_log| must either outlive the IOThread or be NULL.
   IOThread(PrefServiceSimple* local_state,
            policy::PolicyService* policy_service,
            ChromeNetLog* net_log,
            extensions::EventRouterForwarder* extension_event_router_forwarder);
 
   virtual ~IOThread();
 
@@ skipping 115 matching lines @@
   scoped_refptr<net::URLRequestContextGetter>
       system_url_request_context_getter_;
 
   net::SdchManager* sdch_manager_;
 
   // True if SPDY is disabled by policy.
   bool is_spdy_disabled_by_policy_;
 
   base::WeakPtrFactory<IOThread> weak_factory_;
 
+  v8::Isolate* v8_default_isolate_;
+
   DISALLOW_COPY_AND_ASSIGN(IOThread);
 };
 
 #endif  // CHROME_BROWSER_IO_THREAD_H_