[Mac][Material Design] Get Omnibox table width from dropdown window.

chrome/browser/ui/cocoa/omnibox/omnibox_popup_view_mac.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.
 
 #include "chrome/browser/ui/cocoa/omnibox/omnibox_popup_view_mac.h"
 
 #include <cmath>
 
 #include "base/mac/mac_util.h"
 #import "base/mac/sdk_forward_declarations.h"
@@ skipping 242 matching lines @@
   NSRect background_rect = NSZeroRect;
   background_rect.size.width = NSWidth(popup_frame);
   background_rect.size.height = NSHeight(popup_frame) -
       NSHeight(top_separator_frame) - NSHeight(bottom_separator_frame);
   background_rect.origin.y = NSMaxY(top_separator_frame);
   [background_view_ setFrame:background_rect];
 
   // In Material Design, the table is the width of the window. In non-MD,
   // calculate the width of the table based on backing out the popup's border
   // from the width of the field.
-  CGFloat table_width = NSWidth([background_view_ bounds]);
+  CGFloat table_width = NSWidth([[[field_ window] contentView] bounds]);
   bool is_mode_material = ui::MaterialDesignController::IsModeMaterial();
   if (!is_mode_material) {
     table_width = NSWidth([field_ bounds]);
   }
   DCHECK_GT(table_width, 0.0);
 
   // Matrix.
   NSPoint field_origin_base =
       [field_ convertPoint:[field_ bounds].origin toView:nil];
   NSRect matrix_frame = NSZeroRect;
@@ skipping 85 matching lines @@
   return NSImageFromImageSkia(
       gfx::CreateVectorIcon(vector_icon_id, kIconSize, icon_color));
 }
 
 void OmniboxPopupViewMac::OpenURLForRow(size_t row,
                                         WindowOpenDisposition disposition) {
   DCHECK_LT(row, GetResult().size());
   omnibox_view_->OpenMatch(GetResult().match_at(row), disposition, GURL(),
                            base::string16(), row);
 }