views: implement dialog width snapping

chrome/browser/ui/views/harmony/harmony_layout_delegate.cc

 // 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.
 
 #include "chrome/browser/ui/views/harmony/harmony_layout_delegate.h"
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 
 static base::LazyInstance<HarmonyLayoutDelegate>::DestructorAtExit
@@ skipping 62 matching lines @@
 }
 
 bool HarmonyLayoutDelegate::ShouldShowWindowIcon() const {
   return false;
 }
 
 bool HarmonyLayoutDelegate::IsHarmonyMode() const {
   return true;
 }
 
-int HarmonyLayoutDelegate::GetDialogPreferredWidth(DialogWidth width) const {
-  switch (width) {
-    case DialogWidth::SMALL:
-      return 320;
-    case DialogWidth::MEDIUM:
-      return 448;
-    case DialogWidth::LARGE:
-      return 512;
+int HarmonyLayoutDelegate::GetSnappedDialogWidth(int width) const {
+  const int kDefaultWidths[] = {320, 448, 512};
+  for (size_t i = 0; i < arraysize(kDefaultWidths); ++i) {

[tapted, 2017/03/29 23:16:16]

for (int snapped_width : kDefaultWidths) 

(or `width` if the width function arg gets renamed to min_width)

[Elly Fong-Jones, 2017/04/05 18:17:53]

Done.

I actually went one further and made it:
for (int width : {320, 448, 512})

Modern C++ is truly marvellous.

+    if (width <= kDefaultWidths[i])
+      return kDefaultWidths[i];
   }
-  NOTREACHED();
-  return 0;
+  return ((width + kHarmonyLayoutUnit - 1) / kHarmonyLayoutUnit) *
+         kHarmonyLayoutUnit;
 }