Save favicon during reading list distillation

components/dom_distiller/ios/web_state_pool.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_DOM_DISTILLER_IOS_WEB_STATE_POOL_H_
+#define COMPONENTS_DOM_DISTILLER_IOS_WEB_STATE_POOL_H_
+
+namespace web {
+class WebState;
+}
+
+namespace dom_distiller {
+
+// Delegate for the WebStatePool.
+class WebStatePoolDelegate {
+ public:
+  // Called by the pool when |web_state| can be used by the delegate.
+  virtual void OnWebStateAvailable(web::WebState* web_state) = 0;
+};
+
+// Pool for WebStates with Favicon Driver attached. The WebStates from this pool
+// have time to finish the download of the favicons when then are returned,
+// before being reused.
+class WebStatePool {
+ public:
+  // Request a WebState asynchronously. The pool will call |delegate|'s
+  // OnWebStateAvailable when a WebState is available.
+  virtual void RequestWebState(WebStatePoolDelegate* delegate) = 0;
+  // Called by the delegate to return a WebState to the pool. The WebState
+  // should not be used after being returned.
+  virtual void ReturnWebState(web::WebState* web_state) = 0;
+};
+
+}  // namespace dom_distiller
+
+#endif  // COMPONENTS_DOM_DISTILLER_IOS_WEB_STATE_POOL_H_