Add NetworkService support for chrome and chrome-devtools schemes (see issue #2622).

Known behavior changes:
- Unsupported chrome hosts no longer redirect to chrome://version.

To test: All tests pass with NetworkService disabled. WebUITest.* and V8Test.*
tests pass with NetworkService enabled.

libcef/browser/net/devtools_scheme_handler.h

@@ -6,6 +6,7 @@
 #define CEF_LIBCEF_BROWSER_NET_DEVTOOLS_SCHEME_HANDLER_H_
 #pragma once
 
+class CefResourceContext;
 class CefURLRequestManager;
 
 namespace scheme {
@@ -14,6 +15,7 @@ extern const char kChromeDevToolsHost[];
 
 // Register the chrome-devtools scheme handler.
 void RegisterChromeDevToolsHandler(CefURLRequestManager* request_manager);
+void RegisterChromeDevToolsHandler(CefResourceContext* resource_context);
 
 }  // namespace scheme