Introduce networking.cast API

chrome/browser/extensions/api/chrome_extensions_api_client.h

Index: chrome/browser/extensions/api/chrome_extensions_api_client.h
diff --git a/chrome/browser/extensions/api/chrome_extensions_api_client.h b/chrome/browser/extensions/api/chrome_extensions_api_client.h
index 55611b757ca0e17f8656ee7bf6cfa469843db69b..bd5c11636fde5cf23ba245747f660a390e29a0a7 100644
--- a/chrome/browser/extensions/api/chrome_extensions_api_client.h
+++ b/chrome/browser/extensions/api/chrome_extensions_api_client.h
@@ -54,6 +54,7 @@ class ChromeExtensionsAPIClient : public ExtensionsAPIClient {
       const override;
   ManagementAPIDelegate* CreateManagementAPIDelegate() const override;
   MetricsPrivateDelegate* GetMetricsPrivateDelegate() override;
+  NetworkingCastPrivateDelegate* GetNetworkingCastPrivateDelegate() override;
 
 #if defined(OS_CHROMEOS)
   NonNativeFileSystemDelegate* GetNonNativeFileSystemDelegate() override;
@@ -67,6 +68,8 @@ class ChromeExtensionsAPIClient : public ExtensionsAPIClient {
 
  private:
   std::unique_ptr<ChromeMetricsPrivateDelegate> metrics_private_delegate_;
+  std::unique_ptr<NetworkingCastPrivateDelegate>
+      networking_cast_private_delegate_;
 
 #if defined(OS_CHROMEOS)
   std::unique_ptr<NonNativeFileSystemDelegate> non_native_file_system_delegate_;