Tuesday, November 29, 2016

Make file-picker modal in Chromium for Linux

When I stared working on Chromium, I found a bug in Chromium for Linux: the file-picker was not modal. So, while opening a file-picker, the users could control the main window. Sometimes, it caused mis-behaviors such as we were able to send an email while attaching a file.
There was already a bug and it seemed easy to fix it, but, it took 2 years to fully fix the problem.

The root cause is as follows:

Chromium for Linux uses GtkFileChooserDialog to open a file-picker, but it is not modal to the X11 host window because GtkFileChooserDialog can be modal only to the parent GtkWindow. So I tried to allow the X11 host window to disable input event handling to make a file-picker modal:  Here is the details:

Opening a file-picker

DisableEventListening() disables event listening for the host window using aura::ScopedWindowTargeter, which allows to temporarily replace the event-targeter with ui::NullEventTargeter. It returns a scope handle that is used to call |destroy_callback| when closing the file-picker.

class ScopedHandle {
   explicit ScopedHandle(const base::Closure& destroy_callback);
   void CancelCallback();

    base::Closure destroy_callback_;

In addition, we also set another destroy callback(OnFilePickerDestroy) to the GtkFileChooserDialog that can be called when the file-picker is closed.

Close the file-picker

As you can see, OnFilePickerDestroy deletes scoped_handle.
void OnFilePickerDestroy(views::DesktopWindowTreeHostX11::ScopedHandle*
   scoped_handle) {
 delete scoped_handle;

Then, |destroy_callback| of ScopedHandle below is automatically called.
void DesktopWindowTreeHostX11::EnableEventListening() {
 modal_dialog_xid_ = 0;

You can find more details and discussion at here.

The first change list was reverted due to the UI freezing problem that happens when the users open a file-picker from a child window of the X11 host window. The second change list finally fixed this issue(BUG 408481, 579408). I also added a test case for the fix: BrowserSelectFileDialogTest.ModalTest.

Monday, November 14, 2016

My major contributions to Chromium project

I have been working on Chromium project since 2013 and fixed many bugs and implemented some features. Here are my major contributions:

Blink Editing
  1. [Issue 226941] Contenteditable issues related to backspace handling
  2. [Issue 318925] Copy and paste sometimes removes spaces between words
  1. [Issue 310149] ContentEditable:   is forced on SPACE between text nodes
  2. [Issue 335955] Unwanted spans inserted in contentEditable elements
  3. [issue 571420] chrome hangs on when creating bullet list in contenteditable
  1. [Issue 634482] Formatting tags converted to spans with styles on cut/paste
  2. [Issue 625802] Unnecessary quote appears after clicking on indent more option in compose box.
  3. [Issue 582225] document.queryCommandState isn't working well with and
  4. [Issue 584939] document.queryCommandState returns true for bold, italic, underline, and strikethrough after selecting image
  5. [Issue 385374] queryCommandState can return true for both list types
  6. [issue 232188] Caret color issue in content editable element

Aura and Wayland support:

  1. [Issue 408481] System dialogs (e.g. 'Save As...') are not modal on Ubuntu
  2. [Issue 473228] Make *::ShowWithWindowState(minimized, maximized, fullscreen) consistent across platforms
  3. Issue 578890 upstream wayland backend for ozone
  4. Issue 50485 Korean Hangul typing issue