Revert "Prebuilt chromium: update for lollipop"

This reverts commit f75e1810d90727704d044e1428e58b5190b4f60f.
Revert "Prebuilt chromium: Run a check for target device directory"

This reverts commit 8f9b315dd8141b0abbe50fac5fc953bd1db20e73.
Revert "build: Add chromium prebuilt support to envsetup.sh && The core Makefile"

This reverts commit 32905a4ffa7dc1f729c0335ecf0d9407af2004d8.

Conflicts:
	core/Makefile