Add an option to scan for incompatible folders to the WebView license tool.

This is a prerequisite to adding the incompatible folders check to the
AOSP bot.

BUG=329540
TEST=run tool

Review URL: https://codereview.chromium.org/133073008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245560 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245560
Prevented flakiness in FirstRunUIBrowserTest.FirstRunFlow test.

BUG=335280
TEST=browser_test --gtest_filter=FirstRunUIBrowserTest.FirstRunFlow

Review URL: https://codereview.chromium.org/141803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245561 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245561