Fix Harmony popover buttons being flush with their content.

ui/views/layout/layout_provider.cc

 // Copyright 2017 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 "ui/views/layout/layout_provider.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/views/layout/layout_constants.h"
@@ skipping 68 matching lines @@
     case DistanceMetric::DISTANCE_BUTTON_HORIZONTAL_PADDING:
       return kButtonHorizontalPadding;
     case DistanceMetric::DISTANCE_BUTTON_MAX_LINKABLE_WIDTH:
       return 0;
     case DistanceMetric::DISTANCE_CLOSE_BUTTON_MARGIN:
       return kCloseButtonMargin;
     case DistanceMetric::DISTANCE_RELATED_BUTTON_HORIZONTAL:
       return kRelatedButtonHSpacing;
     case DistanceMetric::DISTANCE_RELATED_CONTROL_HORIZONTAL:
       return kRelatedControlHorizontalSpacing;
+    case DistanceMetric::DISTANCE_BUBBLE_BUTTON_TOP_MARGIN:
     case DistanceMetric::DISTANCE_RELATED_CONTROL_VERTICAL:
       return kRelatedControlVerticalSpacing;
     case DISTANCE_DIALOG_BUTTON_BOTTOM_MARGIN:
       return views::kButtonVEdgeMarginNew;
     case DistanceMetric::DISTANCE_DIALOG_BUTTON_MINIMUM_WIDTH:
       return kDialogMinimumButtonWidth;
     case DISTANCE_DIALOG_CONTENTS_HORIZONTAL_MARGIN:
       return kButtonHEdgeMarginNew;
   }
   NOTREACHED();
   return 0;
 }
 
 const TypographyProvider& LayoutProvider::GetTypographyProvider() const {
   return typography_provider_;
 }
 
 int LayoutProvider::GetSnappedDialogWidth(int min_width) const {
   // This is an arbitrary value, but it's a good arbitrary value. Some dialogs
   // have very small widths for their contents views, which causes ugly
   // title-wrapping where a two-word title is split across multiple lines or
   // similar. To prevent that, forbid any snappable dialog from being narrower
   // than this value. In principle it's possible to factor in the title width
   // here, but it is not really worth the complexity.
   return std::max(min_width, 320);
 }
 
 }  // namespace views