Make the v8 Isolate used in the proxy resolver explicit.

net/proxy/proxy_resolver_v8.h

Index: net/proxy/proxy_resolver_v8.h
diff --git a/net/proxy/proxy_resolver_v8.h b/net/proxy/proxy_resolver_v8.h
index c00bb8a4b2465e57ef49f8baa375a87dc61935c8..7d1d51c43f7aac946030ed7ffc33c1925dc8149d 100644
--- a/net/proxy/proxy_resolver_v8.h
+++ b/net/proxy/proxy_resolver_v8.h
@@ -10,6 +10,10 @@
 #include "net/base/net_export.h"
 #include "net/proxy/proxy_resolver.h"
 
+namespace v8 {
+class Isolate;
+}  // namespace v8
+
 namespace net {
 
 class ProxyResolverJSBindings;
@@ -37,7 +41,8 @@ class NET_EXPORT_PRIVATE ProxyResolverV8 : public ProxyResolver {
   // Constructs a ProxyResolverV8 with custom bindings. ProxyResolverV8 takes
   // ownership of |custom_js_bindings| and deletes it when ProxyResolverV8
   // is destroyed.
-  explicit ProxyResolverV8(ProxyResolverJSBindings* custom_js_bindings);
+  ProxyResolverV8(ProxyResolverJSBindings* custom_js_bindings,
+                  v8::Isolate* v8_default_isolate);
 
   virtual ~ProxyResolverV8();
 
@@ -69,6 +74,8 @@ class NET_EXPORT_PRIVATE ProxyResolverV8 : public ProxyResolver {
 
   scoped_ptr<ProxyResolverJSBindings> js_bindings_;
 
+  v8::Isolate* v8_default_isolate_;
+
   DISALLOW_COPY_AND_ASSIGN(ProxyResolverV8);
 };