Move FindPasteboard to ui/base/cocoa since it's used by two modules (content+chrome).

content/browser/find_pasteboard.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 CONTENT_BROWSER_FIND_PASTEBOARD_H_
-#define CONTENT_BROWSER_FIND_PASTEBOARD_H_
-#pragma once
-
-#include "base/string16.h"
-
-#ifdef __OBJC__
-
-#import <Cocoa/Cocoa.h>
-
-#include "base/memory/scoped_nsobject.h"
-#include "content/common/content_export.h"
-
-CONTENT_EXPORT extern NSString* kFindPasteboardChangedNotification;
-
-// Manages the find pasteboard. Use this to copy text to the find pasteboard,
-// to get the text currently on the find pasteboard, and to receive
-// notifications when the text on the find pasteboard has changed. You should
-// always use this class instead of accessing
-// [NSPasteboard pasteboardWithName:NSFindPboard] directly.
-//
-// This is not thread-safe and must be used on the main thread.
-//
-// This is supposed to be a singleton.
-@interface FindPasteboard : NSObject {
- @private
-  scoped_nsobject<NSString> findText_;
-}
-
-// Returns the singleton instance of this class.
-+ (FindPasteboard*)sharedInstance;
-
-// Returns the current find text. This is never nil; if there is no text on the
-// find pasteboard, this returns an empty string.
-- (NSString*)findText;
-
-// Sets the current find text to |newText| and sends a
-// |kFindPasteboardChangedNotification| to the default notification center if
-// it the new text different from the current text. |newText| must not be nil.
-- (void)setFindText:(NSString*)newText;
-@end
-
-@interface FindPasteboard (TestingAPI)
-- (void)loadTextFromPasteboard:(NSNotification*)notification;
-
-// This methods is meant to be overridden in tests.
-- (NSPasteboard*)findPboard;
-@end
-
-#endif  // __OBJC__
-
-// Also provide a c++ interface
-CONTENT_EXPORT string16 GetFindPboardText();
-
-#endif  // CONTENT_BROWSER_FIND_PASTEBOARD_H_