Move desktop picker ui implementation out of extensions

This CL moves the picker UI triggered from extensions into
DesktopMediaPickerFactoryImpl which lives under
/chrome/browser/media. We are planning to use this common
implementation to trigger the same picker UI for getDisplayMedia().

Bug: 326740
Change-Id: Idb8b9d094ce55ecc8281c3db1f1acb0f5e3a24f1
Reviewed-on: https://chromium-review.googlesource.com/1169594
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Reviewed-by: Weiyong Yao <braveyao@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581953}
10 files changed