views: support dialog width snapping once and for all

chrome/browser/ui/views/harmony/harmony_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 "chrome/browser/ui/views/harmony/harmony_layout_provider.h"
 
 gfx::Insets HarmonyLayoutProvider::GetInsetsMetric(int metric) const {
   DCHECK_LT(metric, views::VIEWS_INSETS_MAX);
   switch (metric) {
     case views::INSETS_DIALOG_BUTTON:
@@ skipping 77 matching lines @@
 }
 
 bool HarmonyLayoutProvider::ShouldShowWindowIcon() const {
   return false;
 }
 
 bool HarmonyLayoutProvider::IsHarmonyMode() const {
   return true;
 }
 
-int HarmonyLayoutProvider::GetDialogPreferredWidth(DialogWidth width) const {
-  switch (width) {
-    case DialogWidth::SMALL:
-      return 320;
-    case DialogWidth::MEDIUM:
-      return 448;
-    case DialogWidth::LARGE:
-      return 512;
+int HarmonyLayoutProvider::GetSnappedDialogWidth(int min_width) const {
+  for (int snap_point : {320, 448, 512}) {
+    if (min_width <= snap_point)
+      return snap_point;
   }
-  NOTREACHED();
-  return 0;
+
+  return ((min_width + kHarmonyLayoutUnit - 1) / kHarmonyLayoutUnit) *
+         kHarmonyLayoutUnit;
 }
 
 const views::TypographyProvider& HarmonyLayoutProvider::GetTypographyProvider()
     const {
   return typography_provider_;
 }