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

chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.mm

Index: chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.mm
===================================================================
--- chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.mm	(revision 125450)
+++ chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.mm	(working copy)
@@ -17,11 +17,11 @@
 #include "chrome/browser/ui/find_bar/find_bar_controller.h"
 #include "chrome/browser/ui/find_bar/find_tab_helper.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
-#import "content/browser/find_pasteboard.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #import "third_party/GTM/AppKit/GTMNSAnimation+Duration.h"
+#import "ui/base/clipboard/find_pasteboard.h"
 #import "ui/base/cocoa/focus_tracker.h"
 
 const float kFindBarOpenDuration = 0.2;