Encrypted Media: Handle blink::WebString in WebMediaPlayer*.
This CL converts blink::WebString to std::string in WebMediaPlayerImpl and WebMediaPlayerAndroid so that internal chromium classes don't need to deal with blink::WebString anymore.
Changes about logging:
- Use base::string16 so that if non-ascii parameters can be shown correctly.
- Move logging to public methods so that parameters can be logged before being converted to ASCII.
BUG=252065
TEST=KeySystemsTest updated.
R=ddorwin@chromium.org
Review URL: https://codereview.chromium.org/
170783010
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252160 0039d316-1c4b-4281-b951-d872f2087c98