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 fb73e5a934c547f8994fa1efa1772040c4f92ee0..07bc20214338d800d1add38df395c4f4222414c9 100644
--- a/chrome/browser/ui/views/desktop_media_picker_views.cc
+++ b/chrome/browser/ui/views/desktop_media_picker_views.cc
@@ -5,10 +5,14 @@
 #include "chrome/browser/ui/views/desktop_media_picker_views.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/ui/ash/ash_util.h"
 #include "chrome/browser/ui/views/constrained_window_views.h"
+#include "chrome/common/chrome_switches.h"
 #include "components/web_modal/popup_manager.h"
+#include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/generated_resources.h"
 #include "ui/aura/window_tree_host.h"
@@ -59,6 +63,35 @@ int GetMediaListViewHeightForRows(size_t rows) {
   return kListItemHeight * rows;
 }
 
+static bool ShouldAutoSelectSource(const DesktopMediaList::Source& source) {

[Peter Kasting, 2014/08/13 17:17:50]

Nit: "static" unnecessary (you're already in an anonymous namespace)

Especially with the shortening suggestion below I'd probably just inline this
into the lone caller, but up to you.

[phoglund_chromium, 2014/08/14 13:16:24]

Done. Inlining worked out pretty nicely with your shorter version.

+  std::string desired_source =
+      CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          switches::kAutoSelectDesktopCaptureSource);
+  if (desired_source.empty())
+    return false;
+
+  return desired_source == base::UTF16ToASCII(source.name);

[Peter Kasting, 2014/08/13 17:17:50]

Nit: Shorter:

  return !desired_source.empty() &&
      (base::ASCIIToUTF16(desired_source) == source.name);

(I chose to upconvert to UTF-16 instead of downconverting to ASCII in order to
avoid implying anything about whether source.name is actually ASCII.)

[phoglund_chromium, 2014/08/14 13:16:24]

Done.

+}
+
+class AutoSelectTask: public base::RefCounted<AutoSelectTask> {

[Peter Kasting, 2014/08/13 17:17:50]

Does this really need to be refcounted?  Seems like the posted task could just
own this object.

Nit: Space before single colon

[phoglund_chromium, 2014/08/14 13:16:24]

Nope, went with jiayl's solution instead.

+ public:
+  explicit AutoSelectTask(const base::WeakPtr<DesktopMediaListView>& list_view)
+      : list_view_(list_view) {}
+
+  void AcceptSelectedSource() {
+    if (list_view_) {
+      list_view_->OnSelectionChanged();
+      list_view_->OnDoubleClick();
+    }
+  }
+
+ private:
+  friend class base::RefCounted<AutoSelectTask>;
+  ~AutoSelectTask() {}
+
+  base::WeakPtr<DesktopMediaListView> list_view_;
+};

[Peter Kasting, 2014/08/13 17:17:50]

Nit: DISALLOW_COPY_AND_ASSIGN

[phoglund_chromium, 2014/08/14 13:16:24]

Acknowledged.

+
 }  // namespace
 
 DesktopMediaSourceView::DesktopMediaSourceView(
@@ -199,7 +232,8 @@ DesktopMediaListView::DesktopMediaListView(
     DesktopMediaPickerDialogView* parent,
     scoped_ptr<DesktopMediaList> media_list)
     : parent_(parent),
-      media_list_(media_list.Pass()) {
+      media_list_(media_list.Pass()),
+      weak_factory_(this) {
   media_list_->SetThumbnailSize(gfx::Size(kThumbnailWidth, kThumbnailHeight));
 }
 
@@ -314,6 +348,18 @@ void DesktopMediaListView::OnSourceAdded(int index) {
 
   if (child_count() % kListColumns == 1)
     parent_->OnMediaListRowsChanged();
+
+  if (ShouldAutoSelectSource(source)) {
+    // Focusing on the element will select it.
+    source_view->OnFocus();
+
+    // Accept and close the dialog when we're done adding sources.
+    scoped_refptr<AutoSelectTask> task(
+        new AutoSelectTask(weak_factory_.GetWeakPtr()));
+    content::BrowserThread::PostTask(
+        content::BrowserThread::UI, FROM_HERE,
+        base::Bind(&AutoSelectTask::AcceptSelectedSource, task));

[jiayl, 2014/08/13 17:32:42]

AutoSelectTask is not needed.
You can just do

PostTask(UI, FROM_HERE,    
    base::Bind(&DesktopMediaListView::AcceptSelection,     
               weak_factory_.GetWeakPtr());
 
DesktopMediaListView::AcceptSelection() {
  OnSelectionChanged();
  OnDoubleClick();
}

[phoglund_chromium, 2014/08/14 13:16:24]

So PostTask is smart enough to check the weak pointer? Nice.

+  }
 }
 
 void DesktopMediaListView::OnSourceRemoved(int index) {