Add command-line flag for tests to bypass the screenshare window picker.

chrome/browser/ui/views/desktop_media_picker_views.cc

Index: chrome/browser/ui/views/desktop_media_picker_views.cc
diff --git a/chrome/browser/ui/views/desktop_media_picker_views.cc b/chrome/browser/ui/views/desktop_media_picker_views.cc
index 9e21558ab41626f2653c01dc77cfdb0eeac42430..560191dd6f2297662d79caea55c9dc75b935aca8 100644
--- a/chrome/browser/ui/views/desktop_media_picker_views.cc
+++ b/chrome/browser/ui/views/desktop_media_picker_views.cc
@@ -5,10 +5,13 @@
 #include "chrome/browser/media/desktop_media_picker.h"
 
 #include "base/callback.h"
+#include "base/command_line.h"
+#include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/media/desktop_media_list.h"
 #include "chrome/browser/media/desktop_media_list_observer.h"
 #include "chrome/browser/ui/ash/ash_util.h"
 #include "chrome/browser/ui/views/constrained_window_views.h"
+#include "chrome/common/chrome_switches.h"
 #include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/generated_resources.h"
@@ -62,6 +65,16 @@ int GetMediaListViewHeightForRows(size_t rows) {
   return kListItemHeight * rows;
 }
 
+static bool ShouldAutoSelectSource(const DesktopMediaList::Source& source) {
+  std::string desired_source =
+      CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          switches::kAutoSelectDesktopCaptureSource);
+  if (desired_source.empty())
+    return false;
+
+  return desired_source == base::UTF16ToASCII(source.name);
+}
+
 class DesktopMediaListView;
 class DesktopMediaPickerDialogView;
 class DesktopMediaPickerViews;
@@ -473,6 +486,7 @@ void DesktopMediaListView::OnSourceAdded(int index) {
   DesktopMediaSourceView* source_view =
       new DesktopMediaSourceView(this, source.id);
   source_view->SetName(source.name);
+  std::cout << "!!! " << source.name << std::endl;
   source_view->SetGroup(kDesktopMediaSourceViewGroupId);
   AddChildViewAt(source_view, index);
 
@@ -480,6 +494,12 @@ void DesktopMediaListView::OnSourceAdded(int index) {
 
   if (child_count() % kListColumns == 1)
     parent_->OnMediaListRowsChanged();
+
+  if (ShouldAutoSelectSource(source)) {

[jiayl, 2014/07/09 17:02:34]

It's not safe to do these in this callback, as it will cause the window and the
backing objects (including the media_list_) destroyed while the caller
(media_list_) is looping to add more sources. You may PostTask instead.

[phoglund_chromium, 2014/08/04 12:37:25]

Oh, right. Umm, I'm not very familiar with Chrome threading so please help me
out. So I would like to post a task to run OnSelectionChanged and OnDoubleClick,
but only when the caller is done adding sources. I can't post to this object
though because it is not reference counted, and therefore I can't base::Bind it
(right?)

I looked at the calling code in for instance
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/med...,
and I considered moving the bypass code there. Like, when done adding all
sources, check if we should forcibly select one of them, to avoid the problem
you outline above. However that method doesn't have a way to forcibly select an
entry since it talks to the view through an observer interface where we can't
call OnDoubleClick and the like. Which is nice design, since it prevents such a
horrible hack :)

So the fundamental problem is to wait to some suitable safe time when the dialog
has been populated, and then go through the media_list and see if the source
we're waiting for has appeared. Is there some method that gets called when we
can safely call OnSelectionChanged etc? If so I could just hook up this
find-and-doubleclick code there. Otherwise I guess I need to set up some kind of
periodical task (if flag is specified, set up a task which periodically polls
the source list for the desired source).

+    source_view->SetSelected(true);
+    OnSelectionChanged();
+    parent_->OnDoubleClick();
+  }
 }
 
 void DesktopMediaListView::OnSourceRemoved(int index) {