build: Add chromium prebuilt support to envsetup.sh && The core Makefile

This adds a chromium_prebuilt function to envsetup.sh that is invoked by lunch to check
whether the chromium prebuilt are up-to-date or not. If not, it will be built from source
and then the new source built version will be pulled during brunch/mka bacon to become the
new prebuilts for future builds.

This is all opt-in through the USE_PREBUILT_CHROMIUM flag. Without it being set to 1,
none of this would be ran, and regular operations will go on.

PS13:
-use export TARGET_DEVICE
-replace git -C with params compatible to old git versions

Change-Id: I40f8c8dbd2a8a84a5c1b9f47ee04180a71ef4e07
Prebuilt chromium: Run a check for target device directory

This should fix the issue that arises if device fails
and device is built again, chromium will error out because it thinks
the prebuilt files exist (which they are not, directories are just created).

Signed-off-by: Ayysir <ayysir@aospal.com>
Change-Id: I595cab268e66c738ccae9900150b36d7f9626a6e

(cherry picked from commit 8060cfea57d1336a91308323ffddab15fe43b2cc)
build: Fix PreBuilt Chromium refs

Change-Id: Icc553d5be1e71d8c754bc85b6906252e5690b508

(cherry picked from commit 4701b3f41c1e84eded7295cc2cd5fff15e1c091d)
build: change style console output of prebuilt chromium

Change-Id: I2c390f3c64d614e181ebcad4e9711a93d9c55d44

(cherry picked from commit aa92d91d5a19e519b9be3e6694f4cdfdbebbbfb1)