Adds speech recognition test case to AppListStartPageWebUITest.

BUG=341926
R=xiyuan@chromium.org
TEST=browser_tests

Review URL: https://codereview.chromium.org/159973004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251360 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251360
In order to show the poster image while casting a video, we pass the poster image URL to Android. Like favicons, it will be downloaded and be shown in the relevant activity & view.

Relevant CLs:
Blink: https://codereview.chromium.org/131763011/
Chrome for Android: https://chrome-internal-review.googlesource.com/#/c/153405/

BUG=333260
NOTRY=true

Review URL: https://codereview.chromium.org/135863004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251361 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251361