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.cc

@@ -8,6 +8,7 @@
 
 #include "libcef/browser/net/internal_scheme_handler.h"
 #include "libcef/browser/net/url_request_manager.h"
+#include "libcef/browser/resource_context.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
@@ -46,4 +47,10 @@ void RegisterChromeDevToolsHandler(CefURLRequestManager* request_manager) {
       CreateInternalHandlerFactory(base::WrapUnique(new Delegate())));
 }
 
+void RegisterChromeDevToolsHandler(CefResourceContext* resource_context) {
+  resource_context->RegisterSchemeHandlerFactory(
+      content::kChromeDevToolsScheme, kChromeDevToolsHost,
+      CreateInternalHandlerFactory(base::WrapUnique(new Delegate())));
+}
+
 }  // namespace scheme