Bug Fix: Desktop Picker Window Shows Unnecessary Scrollbar

chrome/browser/ui/views/desktop_capture/desktop_media_list_view.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/desktop_capture/desktop_media_list_view.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 100 matching lines @@
     if (i > 0 && i % active_style_->columns == 0) {
       x = 0;
       y += active_style_->item_size.height();
     }
 
     child_at(i)->SetBounds(x, y, active_style_->item_size.width(),
                            active_style_->item_size.height());
 
     x += active_style_->item_size.width();
   }
+
+  // TODO(qiangchen): Bounded ScrollView has a bug to display horizontal bar
+  // always, and then display vertical bar when the content just fit the
+  // container. See crbug/636338.
+  // Fix the underlying issue and remove the following code.
+  gfx::Size parent_content_size = parent()->GetContentsBounds().size();
+  SetSize(gfx::Size(parent_content_size.width(),

[sky, 2016/09/06 18:08:50]

It seems like you have an inherent preferred width based on the number of
columns/children? I'm suggesting the with should be a
std::max(parent_content_size.width(), GetPreferredSize().width())
I have GetPreferredSize().width(), but I suspect you could also calculate the
pref width in this function as well.

[qiangchen, 2016/09/06 18:38:10]

Done.

+                    std::max(parent_content_size.height(),
+                             y + active_style_->item_size.height())));
 }
 
 bool DesktopMediaListView::OnKeyPressed(const ui::KeyEvent& event) {
   int position_increment = 0;
   switch (event.key_code()) {
     case ui::VKEY_UP:
       position_increment = -active_style_->columns;
       break;
     case ui::VKEY_DOWN:
       position_increment = active_style_->columns;
@@ skipping 142 matching lines @@
 }
 
 DesktopMediaSourceView* DesktopMediaListView::GetChild(int index) {
   return static_cast<DesktopMediaSourceView*>(child_at(index));
 }
 
 void DesktopMediaListView::GetAccessibleState(ui::AXViewState* state) {
   state->role = ui::AX_ROLE_GROUP;
   state->name = accessible_name_;
 }