base: Add basic ReadValue test to RegistryTest.
base: Add basic ReadValue test to RegistryTest.

BUG=None
TEST=out/Debug/base_unittests --gtest_filter=RegistryTest.*

Review URL: http://codereview.chromium.org/3190010

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@56965 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser