Fix Harmony popover buttons being flush with their content.

chrome/browser/ui/views/harmony/chrome_layout_provider.h

 // Copyright 2016 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 CHROME_BROWSER_UI_VIEWS_HARMONY_CHROME_LAYOUT_PROVIDER_H_
 #define CHROME_BROWSER_UI_VIEWS_HARMONY_CHROME_LAYOUT_PROVIDER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/views/layout/grid_layout.h"
 #include "ui/views/layout/layout_provider.h"
 
 enum ChromeDistanceMetric {
   // Default minimum width of a button.
   DISTANCE_BUTTON_MINIMUM_WIDTH = views::VIEWS_DISTANCE_END,
   // Vertical spacing between a list of multiple controls in one column.
   DISTANCE_CONTROL_LIST_VERTICAL,
-  // Spacing between a dialog button and the content above it.
-  DISTANCE_DIALOG_BUTTON_TOP,
   // Smaller horizontal spacing between other controls that are logically
   // related.
   DISTANCE_RELATED_CONTROL_HORIZONTAL_SMALL,
   // Smaller vertical spacing between controls that are logically related.
   DISTANCE_RELATED_CONTROL_VERTICAL_SMALL,
   // Horizontal spacing between an item such as an icon or checkbox and a
   // label related to it.
   DISTANCE_RELATED_LABEL_HORIZONTAL,
   // Horizontal indent of a subsection relative to related items above, e.g.
   // checkboxes below explanatory text/headings.
@@ skipping 40 matching lines @@
   // types, e.g. by adding a new LayoutDistance value that means what you need.
   //
   // TODO(pkasting): Fix callers and remove this.
   virtual bool IsHarmonyMode() const;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeLayoutProvider);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_HARMONY_CHROME_LAYOUT_PROVIDER_H_