Mac:Dont always enable findbar buttons when restoring focus with search string

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

 // 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/auto_reset.h"
 #include "base/mac/bundle_locations.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/app/vector_icons/vector_icons.h"
@@ skipping 344 matching lines @@
     showHideAnimation_.reset(nil);
   }
   if (moveAnimation_.get()) {
     [moveAnimation_ stopAnimation];
     moveAnimation_.reset(nil);
   }
 }
 
 - (void)setFocusAndSelection {
   [[findText_ window] makeFirstResponder:findText_];
-
-  // Enable the buttons if the find text is non-empty.

[rohitrao (ping after 24h), 2017/06/13 00:23:37]

I'm worried that this code existed for a reason that we're not considering.  For
example, something involving restoring state after a tab switch.

It does seem odd that we're setting button state here, since this method
purports to be about setting focus and selection.  But I don't want to delete
the code outright without verifying that it's actually not needed by any other
scenario.

-  BOOL buttonsEnabled = ([[findText_ stringValue] length] > 0) ? YES : NO;
-  [previousButton_ setEnabled:buttonsEnabled];
-  [nextButton_ setEnabled:buttonsEnabled];
 }
 
 - (void)restoreSavedFocus {
   if (!(focusTracker_.get() &&
         [focusTracker_ restoreFocusInWindow:[findBarView_ window]])) {
     // Fall back to giving focus to the tab contents.
     findBarBridge_->GetFindBarController()->web_contents()->Focus();
   }
   focusTracker_.reset(nil);
 }
@@ skipping 282 matching lines @@
 }
 
 - (BrowserWindowController*)browserWindowController {
   if (!browser_)
     return nil;
   return [BrowserWindowController
       browserWindowControllerForWindow:browser_->window()->GetNativeWindow()];
 }
 
 @end