DevTools: Move WebInspector.{log,showErrorMessage} into ConsoleModel.

Drive-by: Remove obsolete code making sure log() works when
there is no WebInspector.console available.

R=eustas, pfeldman, vsevik

Review URL: https://codereview.chromium.org/197073005

git-svn-id: svn://svn.chromium.org/blink/trunk@169016 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: speedup editor file viewing on files more 10Mb

This patch forces text editor readonly mode on files more then 10Mb.
Additionally it:
- eliminates calls to autocompletion dictionary in case of readonly
editor mode
- doesn't go through more then 100000 lines to detect indentation

BUG=

Review URL: https://codereview.chromium.org/196633003

git-svn-id: svn://svn.chromium.org/blink/trunk@169017 bbb929c8-8fbe-4397-9dbb-9b2b20218538