Revert 156787 "DevTools: restore command line API functionality ..."

Caused browser test failure for WorkerDevToolsSanityTest.InspectSharedWorker:
http://build.chromium.org/p/chromium.webkit/builders/Linux%20Tests/builds/30600
http://build.chromium.org/p/chromium.webkit/builders/Win7%20%28dbg%29/builds/11924


> DevTools: restore command line API functionality while on a breakpoint.
> 
> Review URL: https://chromiumcodereview.appspot.com/23495003

TBR=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/23543004

git-svn-id: svn://svn.chromium.org/blink/trunk@156795 bbb929c8-8fbe-4397-9dbb-9b2b20218538