DevTools: [CodeMirror] support multiple selection in BlockIndentController

The patch fixes the code of BlockIndentController to support multiple
selections.

BUG=388640

Review URL: https://codereview.chromium.org/353423002

git-svn-id: svn://svn.chromium.org/blink/trunk@177513 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: reveal console in drawer on "evaluate in console" command

Reveal console view in drawer on "evaluate in console" command from
JavaScriptSourceFrame.

BUG=389501

Review URL: https://codereview.chromium.org/368243003

git-svn-id: svn://svn.chromium.org/blink/trunk@177514 bbb929c8-8fbe-4397-9dbb-9b2b20218538
add trace events to XMLDocumentParser

XMLDocumentParser is expected to be slow and we plan to use HTMLDocumentParser as much as possbile.
These tracing events measuring time spent inside parser would help us understand its potential impact.

BUG=None

Review URL: https://codereview.chromium.org/368243008

git-svn-id: svn://svn.chromium.org/blink/trunk@177515 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add UseCounter for MediaStreamTrack.getSources.

MediaStreamTrack.getSources is planned to be removed in M40.

NOTRY=true

BUG=388194

Review URL: https://codereview.chromium.org/370543002

git-svn-id: svn://svn.chromium.org/blink/trunk@177516 bbb929c8-8fbe-4397-9dbb-9b2b20218538