[Android] Upstream the WebView find-in-page API implementation.

android_webview/browser/find_helper.h

+// Copyright (c) 2012 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 ANDROID_WEBVIEW_BROWSER_FIND_HELPER_H_
+#define ANDROID_WEBVIEW_BROWSER_FIND_HELPER_H_
+
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace android_webview {
+
+// Handles the WebView find-in-page API requests.
+class FindHelper : public content::WebContentsObserver {
+ public:
+  class Listener {
+   public:
+    // Called when receiving a new find-in-page update.
+    // This will be triggered when the results of FindAllSync, FindAllAsync and
+    // FindNext are available. The value provided in active_ordinal is 0-based.
+    virtual void OnFindResultReceived(int active_ordinal,
+                                      int match_count,
+                                      bool finished) = 0;
+    virtual ~Listener() {}
+  };
+
+  explicit FindHelper(content::WebContents* web_contents);
+  virtual ~FindHelper();
+
+  // Sets the listener to receive find result updates.
+  // Does not own the listener and must set to NULL when invalid.
+  void SetListener(Listener* listener);
+
+  // Synchronous API.
+  int FindAllSync(const string16& search_string);
+
+  // Asynchronous API.
+  void FindAllAsync(const string16& search_string);
+  void HandleFindReply(int request_id,
+                       int match_count,
+                       int active_ordinal,
+                       bool finished);
+
+  // Methods valid in both synchronous and asynchronous modes.
+  void FindNext(bool forward);
+  void ClearMatches();
+
+ private:
+  void StartNewRequest(const string16& search_string);
+  void NotifyResults(int active_ordinal, int match_count, bool finished);
+
+  // Listener results are reported to.
+  Listener* listener_;
+
+  // Used to check the validity of FindNext operations.
+  bool async_find_started_;
+  bool sync_find_started_;
+
+  // Used to provide different ids to each request and for result
+  // verification in asynchronous calls.
+  int find_request_id_counter_;
+  int current_request_id_;
+
+  // Required by FindNext and the incremental find replies.
+  string16 last_search_string_;
+  int last_match_count_;
+  int last_active_ordinal_;
+
+  // Used to post synchronous result notifications to ourselves.
+  base::WeakPtrFactory<FindHelper> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(FindHelper);
+};
+
+}  // namespace android_webview
+
+#endif  // ANDROID_WEBVIEW_BROWSER_FIND_HELPER_H_