Introduce networking.cast API

extensions/browser/api/extensions_api_client.h

Index: extensions/browser/api/extensions_api_client.h
diff --git a/extensions/browser/api/extensions_api_client.h b/extensions/browser/api/extensions_api_client.h
index be47c889e80597e77b30bf02745753a0be5699a7..ed1cba2d200c96dfbf3184727a9c40214a18a3d6 100644
--- a/extensions/browser/api/extensions_api_client.h
+++ b/extensions/browser/api/extensions_api_client.h
@@ -38,6 +38,7 @@ class ManagementAPIDelegate;
 class MetricsPrivateDelegate;
 class MimeHandlerViewGuest;
 class MimeHandlerViewGuestDelegate;
+class NetworkingCastDelegate;
 class NonNativeFileSystemDelegate;
 class RulesCacheDelegate;
 class SettingsObserver;
@@ -132,6 +133,9 @@ class ExtensionsAPIClient {
   // MetricsPrivateAPI behavior.
   virtual MetricsPrivateDelegate* GetMetricsPrivateDelegate();
 
+  // Creates a delegate for networking cast's API behavior.
+  virtual NetworkingCastDelegate* GetNetworkingCastDelegate();
+
 #if defined(OS_CHROMEOS)
   // If supported by the embedder, returns a delegate for querying non-native
   // file systems.