Add hash to OFC pasteboard change detection

components/open_from_clipboard/clipboard_recent_content_ios.h

 // Copyright 2015 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_OPEN_FROM_CLIPBOARD_CLIPBOARD_RECENT_CONTENT_IOS_H_
 #define COMPONENTS_OPEN_FROM_CLIPBOARD_CLIPBOARD_RECENT_CONTENT_IOS_H_
 
 #include "base/mac/scoped_nsobject.h"
+#include "base/time/time.h"
 #include "components/open_from_clipboard/clipboard_recent_content.h"
 #include "url/gurl.h"
 
 @class NSDate;
+@class NSUserDefaults;
 @class PasteboardNotificationListenerBridge;
 
 class ClipboardRecentContentIOSTest;
 
 // IOS implementation of ClipboardRecentContent
 class ClipboardRecentContentIOS : public ClipboardRecentContent {
  public:
   // |application_scheme| is the URL scheme that can be used to open the
   // current application, may be empty if no such scheme exists. Used to
   // determine whether or not the clipboard contains a relevant URL.
-  explicit ClipboardRecentContentIOS(const std::string& application_scheme);
+  // |group_user_defaults| is the NSUserDefaults used to store information on
+  // pasteboard entry expiration. This information will be shared with other
+  // application in the application group.
+  explicit ClipboardRecentContentIOS(const std::string& application_scheme,
+                                     NSUserDefaults* group_user_defaults);
   ~ClipboardRecentContentIOS() override;
 
   // Notifies that the content of the pasteboard may have changed.
   void PasteboardChanged();
 
+  // Checks if pasteboard changed since last time a pasteboard change was
+  // registered.
+  bool HasPasteboardChanged(base::TimeDelta uptime);
+
+  // Loads information from the user defaults about the latest pasteboard entry.
+  void LoadFromUserDefaults();
+
   // ClipboardRecentContent implementation.
   bool GetRecentURLFromClipboard(GURL* url) const override;
   base::TimeDelta GetClipboardContentAge() const override;
   void SuppressClipboardContent() override;
+  void RecentURLDisplayed() override;
 
  private:
   friend class ClipboardRecentContentIOSTest;
 
   // Helper constructor for testing. |uptime| is how long ago the device has
   // started, while |application_scheme| has the same meaning as the public
   // constructor.
   ClipboardRecentContentIOS(const std::string& application_scheme,
                             base::TimeDelta uptime);
 
   // Initializes the object. |uptime| is how long ago the device has started.
   void Init(base::TimeDelta uptime);
 
-  // Loads information from the user defaults about the latest pasteboard entry.
-  void LoadFromUserDefaults();
-
   // Saves information to the user defaults about the latest pasteboard entry.
   void SaveToUserDefaults();
 
   // Returns the URL contained in the clipboard (if any).
   GURL URLFromPasteboard();
 
   // Contains the URL scheme opening the app. May be empty.
   std::string application_scheme_;
   // The pasteboard's change count. Increases everytime the pasteboard changes.
-  NSInteger lastPasteboardChangeCount_;
+  NSInteger last_pasteboard_change_count_;
   // Estimation of the date when the pasteboard changed.
-  base::scoped_nsobject<NSDate> lastPasteboardChangeDate_;
+  base::scoped_nsobject<NSDate> last_pasteboard_change_date_;
+  // Estimation of the copy date of the last displayed URL.
+  base::scoped_nsobject<NSDate> last_displayed_pasteboard_entry_;
+  // MD5 hash of the last registered pasteboard entry.
+  base::scoped_nsobject<NSData> last_pasteboard_entry_md5_;
   // Cache of the GURL contained in the pasteboard (if any).
-  GURL urlFromPasteboardCache_;
-  // A count identifying the suppressed pasteboard entry. Contains
-  // |NSIntegerMax| if there's no relevant entry to suppress.
-  NSInteger suppressedPasteboardEntryCount_;
+  GURL url_from_pasteboard_cache_;
   // Bridge to receive notification when the pasteboard changes.
   base::scoped_nsobject<PasteboardNotificationListenerBridge>
-      notificationBridge_;
+      notification_bridge_;
+  // The user defaults from the app group used to optimize the pasteboard change
+  // detection.
+  base::scoped_nsobject<NSUserDefaults> shared_user_defaults_;
 
   DISALLOW_COPY_AND_ASSIGN(ClipboardRecentContentIOS);
 };
 
 #endif  // COMPONENTS_OPEN_FROM_CLIPBOARD_CLIPBOARD_RECENT_CONTENT_IOS_H_