views: add Harmony dialog width support

ui/views/window/dialog_delegate.cc

Index: ui/views/window/dialog_delegate.cc
diff --git a/ui/views/window/dialog_delegate.cc b/ui/views/window/dialog_delegate.cc
index 81f636723102cb125094045070ea489f5d154ff3..6b62012e6a254ff95775baad657f24d8d28cd49d 100644
--- a/ui/views/window/dialog_delegate.cc
+++ b/ui/views/window/dialog_delegate.cc
@@ -10,6 +10,7 @@
 #include "build/build_config.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/material_design/material_design_controller.h"
 #include "ui/gfx/color_palette.h"
 #include "ui/strings/grit/ui_strings.h"
 #include "ui/views/bubble/bubble_border.h"
@@ -128,6 +129,10 @@ void DialogDelegate::UpdateButton(LabelButton* button, ui::DialogButton type) {
   button->SetIsDefault(is_default);
 }
 
+DialogDelegate::DialogWidth DialogDelegate::GetDefaultDialogWidth() const {
+  return DIALOG_WIDTH_DEFAULT;
+}
+
 int DialogDelegate::GetDialogButtons() const {
   return ui::DIALOG_BUTTON_OK | ui::DIALOG_BUTTON_CANCEL;
 }
@@ -268,4 +273,18 @@ void DialogDelegateView::ViewHierarchyChanged(
     NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
 }
 
+gfx::Size DialogDelegateView::GetPreferredSize() const {
+  int height = View::GetPreferredSize().height();

[Evan Stade, 2016/09/28 16:14:37]

you should get the width in the switch statement below, then apply
GetHeightForWidth

[Elly Fong-Jones, 2016/09/28 18:44:09]

Done.

+  DialogDelegate::DialogWidth width = DialogDelegate::DIALOG_WIDTH_DEFAULT;
+  if (ui::MaterialDesignController::IsSecondaryUiMaterial())
+    width = GetDefaultDialogWidth();
+  switch (width) {
+    case DialogDelegate::DIALOG_WIDTH_SMALL: return gfx::Size(320, height);
+    case DialogDelegate::DIALOG_WIDTH_MEDIUM: return gfx::Size(448, height);
+    case DialogDelegate::DIALOG_WIDTH_LARGE: return gfx::Size(512, height);
+    default: return View::GetPreferredSize();

[Evan Stade, 2016/09/28 16:14:37]

don't we want to enforce small/medium/large? If we support anything outside this
set of three sizes, it should be the exception rather than the default.

[Evan Stade, 2016/09/28 16:14:37]

nit: better not to have a default --- explicitly list all enum values. That way
when you add a new one, the compiler will complain about an unhandled value.

[Elly Fong-Jones, 2016/09/28 18:44:09]

We do, but we can't right now, until every DialogDelegate has a
GetDefaultDialogWidth that returns a useful value. I'll add a TODO to remove the
WIDTH_DEFAULT case, though.

[Elly Fong-Jones, 2016/09/28 18:44:09]

Done.

[Evan Stade, 2016/09/28 21:12:38]

if every dialogdelegate is going to need to explicitly set this (rather than
defaulting to WIDTH_LARGE or something) we should probably not make it an
overrideable method, because that's a very verbose way to specify the width. It
would be less verbose to pass a param to the ctor or to have a setter (a la
set_margins, set_anchor_view_insets, etc.)

+  }
+  return gfx::Size();
+}
+
 }  // namespace views