Add a new CldDataSource class that can be queried at runtime.
This will allow several "#if defined" statements to be replaced with runtime
checks, simplifying the build process and eliminating the need to generate
multiple libraries for several targets when building Android's chrome_shell
in the presence of non-static CLD data sources.
BUG=367239
TBR=toyoshim
Review URL: https://codereview.chromium.org/
422843009
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@286177 0039d316-1c4b-4281-b951-d872f2087c98