[Autofill] Remove AutofillPopupController::IsWarning()

chrome/browser/ui/cocoa/autofill/autofill_popup_base_view_cocoa.mm

 // Copyright 2014 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 "chrome/browser/ui/cocoa/autofill/autofill_popup_base_view_cocoa.h"
 
 #include "chrome/browser/ui/autofill/autofill_popup_view_delegate.h"
 #include "chrome/browser/ui/autofill/popup_constants.h"
 #include "ui/base/cocoa/window_size_constants.h"
 
@@ skipping 23 matching lines @@
 }
 
 - (NSColor*)subtextColor {
   // Represents #646464.
   return [NSColor colorWithCalibratedRed:100.0 / 255.0
                                    green:100.0 / 255.0
                                     blue:100.0 / 255.0
                                    alpha:1.0];
 }
 
-- (NSColor*)warningColor {
-  // Represents #646464.
-  return [NSColor colorWithCalibratedRed:100.0 / 255.0
-                                   green:100.0 / 255.0
-                                    blue:100.0 / 255.0
-                                   alpha:1.0];
-}
-
 #pragma mark -
 #pragma mark Public methods
 
 - (id)initWithDelegate:(autofill::AutofillPopupViewDelegate*)delegate
                  frame:(NSRect)frame {
   self = [super initWithFrame:frame];
   if (self)
     popup_delegate_ = delegate;
 
   return self;
@@ skipping 113 matching lines @@
 
 - (void)hidePopup {
   // Remove the child window before closing, otherwise it can mess up
   // display ordering.
   NSWindow* window = [self window];
   [[window parentWindow] removeChildWindow:window];
   [window close];
 }
 
 @end