Implement a shell of FindRequestManager, and hook it up to WebContentsImpl.

content/browser/find_request_manager.h

Index: content/browser/find_request_manager.h
diff --git a/content/browser/find_request_manager.h b/content/browser/find_request_manager.h
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+// 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 CONTENT_BROWSER_FIND_REQUEST_MANAGER_H_
+#define CONTENT_BROWSER_FIND_REQUEST_MANAGER_H_
+
+#include <set>
+#include <vector>
+
+#include "content/public/common/stop_find_action.h"
+#include "third_party/WebKit/public/web/WebFindOptions.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/rect_f.h"
+
+namespace content {
+
+class RenderFrameHost;
+class WebContentsImpl;
+
+// FindRequestManager manages all of the find-in-page requests/replies
+// initiated/received through a WebContents. It coordinates searching across
+// multiple (potentially out-of-process) frames, handles the aggregation of find
+// results from each frame, and facilitates active match traversal. It is
+// instantiated once per WebContents, and is owned by that WebContents.
+//
+// TODO(paulmeyer): FindRequestManager is currently incomplete and does not do
+// all of these things yet, but will soon.
+class FindRequestManager {
+ public:
+  explicit FindRequestManager(WebContentsImpl* web_contents);
+  ~FindRequestManager();
+
+  // Initiates a find operation for |search_text| with the options specified in
+  // |options|. |request_id| uniquely identifies the find request.
+  void Find(int request_id,
+            const base::string16& search_text,
+            const blink::WebFindOptions& options);
+
+  // Stops the active find session and clears the general highlighting of the
+  // matches. |action| determines whether the last active match (if any) will be
+  // activated, cleared, or remain highlighted.
+  void StopFinding(StopFindAction action);
+
+  // Called when a reply is received from a frame with the results from a
+  // find request.
+  void OnFindReply(RenderFrameHost* rfh,
+                   int request_id,
+                   int number_of_matches,
+                   const gfx::Rect& selection_rect,
+                   int active_match_ordinal,
+                   bool final_update);
+
+#if defined(OS_ANDROID)
+  // Selects and zooms to the find result nearest to the point (x,y) defined in
+  // find-in-page coordinates.
+  void ActivateNearestFindResult(float x, float y);
+
+  // Requests the rects of the current find matches from the renderer process.
+  void RequestFindMatchRects(int current_version);
+
+  // Called when a reply is received in response to a request for find match
+  // rects.
+  void OnFindMatchRectsReply(RenderFrameHost* rfh,
+                             int version,
+                             const std::vector<gfx::RectF>& rects,
+                             const gfx::RectF& active_rect);
+#endif
+
+ private:
+  // An invalid ID. This value is invalid for any render process ID, render
+  // frame ID, or find request ID.
+  static const int kInvalidId;
+
+  // The request data for a single find request.
+  struct FindRequest {
+    // The find request ID that uniquely identifies this find request.
+    int id = kInvalidId;
+
+    // The text that is being searched for in this find request.
+    base::string16 search_text;
+
+    // The set of find options in effect for this find request.
+    blink::WebFindOptions options;
+
+    FindRequest() = default;
+    FindRequest(int id,
+                const base::string16& search_text,
+                const blink::WebFindOptions& options)
+        : id(id), search_text(search_text), options(options) {}
+  };
+
+  // Send a find IPC containing the find request |request| to the RenderFrame
+  // associated with |rfh|.
+  void SendFindIPC(const FindRequest& request, RenderFrameHost* rfh);
+
+  // Send a stop finding IPC to the RenderFrame associated with |rfh|.
+  void SendStopFindingIPC(StopFindAction action, RenderFrameHost* rfh) const;
+
+  // Reset all of the per-session state for a new find-in-page session.
+  void Reset(const FindRequest& initial_request);
+
+  // Send the find results (as they currently are) to the WebContents.
+  void NotifyFindReply(int request_id, bool final_update) const;
+
+#if defined(OS_ANDROID)
+  // Request the latest find match rects from a frame.
+  void SendFindMatchRectsIPC(RenderFrameHost* rfh);
+
+  // State related to FindMatchRects requests.
+  struct FindMatchRectsState {
+    // The latest find match rects version known by the requester.
+    int request_version = kInvalidId;
+  } match_rects_;
+#endif
+
+  // The WebContents that owns this FindRequestManager.
+  WebContentsImpl* const contents_;
+
+  // The request ID of the initial find request in the current find-in-page
+  // session, which uniquely identifies this session. Request IDs are included
+  // in all find-related IPCs, which allows reply IPCs containing results from
+  // previous sessions (with |request_id| < |current_session_id_|) to be easily
+  // identified and ignored.
+  int current_session_id_;
+
+  // The current find request.
+  FindRequest current_request_;
+
+  // The total number of matches found in the current find-in-page session.
+  int number_of_matches_;
+
+  // The overall active match ordinal for the current find-in-page session.
+  int active_match_ordinal_;
+
+  // The rectangle around the active match, in screen coordinates.
+  gfx::Rect selection_rect_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_FIND_REQUEST_MANAGER_H_