DevTools: [CodeMirror] indent autodetection should fallback to default indent

This patch fixes indent autodetection to fallback to default indent
from user settings instead of "four spaces" value.

This patch additionally adds a change listener on the "autodetect indentation"
setting.

BUG=389109

Review URL: https://codereview.chromium.org/351213006

git-svn-id: svn://svn.chromium.org/blink/trunk@177103 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[DevTools] Separate text autosizing from device metrics override.

BUG=none

Review URL: https://codereview.chromium.org/345723003

git-svn-id: svn://svn.chromium.org/blink/trunk@177104 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Enables Activity Logger to log extension adding the following elements to the DOM:
- script
- link
- anchor
- iframe
- form
- input
- button

BUG=388287

Review URL: https://codereview.chromium.org/349263002

git-svn-id: svn://svn.chromium.org/blink/trunk@177105 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[oilpan]: Move ElementDataCache to the oilpan heap using transition types.

This gets rid of a persistent collection.

R=ager@chromium.org, erik.corry@gmail.com, haraken@chromium.org, oilpan-reviews@chromium.org, tkent@chromium.org, vegorov@chromium.org, zerny@chromium.org
BUG=

Review URL: https://codereview.chromium.org/355133003

git-svn-id: svn://svn.chromium.org/blink/trunk@177106 bbb929c8-8fbe-4397-9dbb-9b2b20218538