Upstream Chrome on iOS source code [10/11].

ios/chrome/browser/web/print_observer.h

+// Copyright 2014 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 IOS_CHROME_BROWSER_WEB_PRINT_OBSERVER_H_
+#define IOS_CHROME_BROWSER_WEB_PRINT_OBSERVER_H_
+
+#include "ios/web/public/web_state/web_state_observer.h"
+
+namespace base {
+class DictionaryValue;
+}  // namespace base
+
+class GURL;
+
+// Handles print requests from JavaScript window.print.
+class PrintObserver : public web::WebStateObserver {
+ public:
+  explicit PrintObserver(web::WebState* web_state);
+  ~PrintObserver() override;
+
+ private:
+  // web::WebStateObserver overrides:
+  void WebStateDestroyed() override;
+
+  // Called when print message is sent by the web page.
+  bool OnPrintCommand(const base::DictionaryValue&, const GURL&, bool);
+  // Stops handling print requests from the web page.
+  void Detach();
+};
+
+#endif  // IOS_CHROME_BROWSER_WEB_PRINT_OBSERVER_H_