Fix DesktopMediaPickerViews positioning

Before this change DesktopMediaPickerViews would center itself on the
page (and be spoofable), which is in conflict with it being a web-modal
dialog that normally attaches to the location bar.

This change also removes the close-x which is out of place for web-modal
dialogs (and redundant with the existing close button).

Bug: chromium:896012
Change-Id: I6d87a626cb5a4a3f2af87667faa3b2a718905202
Reviewed-on: https://chromium-review.googlesource.com/c/1284755
Commit-Queue: Peter Boström <pbos@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600572}

chrome/browser/ui/views/desktop_capture/desktop_media_picker_views.cc

@@ -350,6 +350,10 @@ bool DesktopMediaPickerDialogView::Accept() {
   return true;
 }
 
+bool DesktopMediaPickerDialogView::ShouldShowCloseButton() const {
+  return false;
+}
+
 void DesktopMediaPickerDialogView::DeleteDelegate() {
   // If the dialog is being closed then notify the parent about it.
   if (parent_)
@@ -377,12 +381,23 @@ void DesktopMediaPickerDialogView::SelectTab(
 }
 
 void DesktopMediaPickerDialogView::OnMediaListRowsChanged() {
-  gfx::Rect widget_bound = GetWidget()->GetWindowBoundsInScreen();
-
-  int new_height = widget_bound.height() - pane_->height() +
-                   pane_->GetPreferredSize().height();
+  PreferredSizeChanged();
+  // TODO(pbos): Ideally this would use shared logic similar to
+  // BubbleDialogDelegateView::SizeToContents() instead of implementing sizing
+  // logic in-place.
+  const gfx::Size new_size = GetWidget()->GetRootView()->GetPreferredSize();
+  if (modality_ == ui::ModalType::MODAL_TYPE_CHILD) {
+    // For the web-modal dialog resize the dialog in place.
+    // TODO(pbos): This should ideally use UpdateWebContentsModalDialogPosition
+    // to keep the widget centered horizontally. As this dialog is fixed-width
+    // we're effectively only changing the height, so reusing the current
+    // widget origin should be equivalent.
+    GetWidget()->SetSize(new_size);
+    return;
+  }
 
-  GetWidget()->CenterWindow(gfx::Size(widget_bound.width(), new_height));
+  // When not using the web-modal dialog, center the dialog with its new size.
+  GetWidget()->CenterWindow(new_size);
 }
 
 DesktopMediaListView* DesktopMediaPickerDialogView::GetMediaListViewForTesting()

chrome/browser/ui/views/desktop_capture/desktop_media_picker_views.h

@@ -52,6 +52,7 @@ class DesktopMediaPickerDialogView : public views::DialogDelegateView,
   base::string16 GetDialogButtonLabel(ui::DialogButton button) const override;
   View* CreateExtraView() override;
   bool Accept() override;
+  bool ShouldShowCloseButton() const override;
   void DeleteDelegate() override;
 
   void OnMediaListRowsChanged();