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/chrome_scheme_handler.h

@@ -23,15 +23,16 @@ namespace content {
 class BrowserURLHandler;
 }
 
+namespace url {
+class Origin;
+}
+
 class CefURLRequestManager;
 
 namespace scheme {
 
 extern const char kChromeURL[];
 
-// Register the chrome scheme handler.
-void RegisterChromeHandler(CefURLRequestManager* request_manager);
-
 // Register the WebUI controller factory.
 void RegisterWebUIControllerFactory();
 
@@ -41,6 +42,9 @@ void BrowserURLHandlerCreated(content::BrowserURLHandler* handler);
 // Used to fire any asynchronous content updates.
 void DidFinishChromeLoad(CefRefPtr<CefFrame> frame, const GURL& validated_url);
 
+// Returns true if WebUI is allowed to make network requests.
+bool IsWebUIAllowedToMakeNetworkRequests(const url::Origin& origin);
+
 // Create a new ProtocolHandler that will filter the URLs passed to the default
 // "chrome" protocol handler and forward the rest to CEF's handler.
 std::unique_ptr<net::URLRequestJobFactory::ProtocolHandler>