Change Add Supervision dialog height to 640px

Bug: 927957
Change-Id: Iba5628ea881350cff723a2ec9116f7fe3adba5ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1664430
Commit-Queue: Felipe Cerqueira <cerqueira@google.com>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670248}

chrome/browser/ui/webui/chromeos/add_supervision/add_supervision_ui.cc

@@ -25,7 +25,7 @@
 
 namespace {
 
-constexpr int kDialogHeightPx = 672;
+constexpr int kDialogHeightPx = 640;
 constexpr int kDialogWidthPx = 768;
 // Id of System Dialog used to show the Add Supervision flow.
 std::string& GetDialogId() {