views: implement width snapping for DialogDelegateViews

chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc

Index: chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
diff --git a/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc b/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
index 2d35985af1b6b1267a775c7083a3fdc3f1794506..965d6d1a99947edf09454a3ba4420eaf44339a66 100644
--- a/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
+++ b/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
@@ -244,7 +244,7 @@ views::View* CardUnmaskPromptViews::CreateFootnoteView() {
   return storage_row_;
 }
 
-gfx::Size CardUnmaskPromptViews::GetPreferredSize() const {
+gfx::Size CardUnmaskPromptViews::GetUnsnappedPreferredSize() const {
   // Must hardcode a width so the label knows where to wrap.

[Peter Kasting, 2017/03/30 00:35:34]

Nit: I suggest filing a followup bug on computing label preferred sizes more
like was suggested in our discussion, and adding a TODO here to fix this.

It seems like simply hardcoding a number for the entire dialog is poor in this
case anyway, as the string is not necessarily going to wrap in all (or even
most?) languages, and we should be computing something more fine-grained.

   const int kWidth = 375;
   return gfx::Size(kWidth, GetHeightForWidth(kWidth));

[Peter Kasting, 2017/03/30 00:35:34]

This line exposes a problem I didn't fully think through, and it happens in
multiple dialogs.

Let's say a dialog wants to be 330 px wide, and it computes a 200 px height for
that width.  With this CL, we'll snap the width to 448 px and return a preferred
size of (448, 200).  But this may leave a bad-looking amount of blank space at
the bottom of the dialog if GetHeightForWidth(448) would have returned something
< 200.

I think we should do something like this:

* Change GetUnsnappedPreferredSize() to GetPreferredWidth() and return an int.
* Implement DialogDelegateView::GetPreferredSize() by snapping
GetPreferredWidth() and then calling GetHeightForWidth() to compute the height.
* Ensure GetHeightForWidth() will do the Right Thing on all dialogs (it probably
already does for most).