Make pkg_resources an optional import for ChromeRunner.
Make pkg_resources an optional import for ChromeRunner.

This lets ChromeRunner be used in environments where pkg_resources is not required, and where no resources are bundled. It will be used in the upcoming SyzyASAN smoke test.

BUG=
R=siggi@chromium.org

Review URL: https://codereview.appspot.com/14043044

git-svn-id: db59699583a60be9a535cd09cdc9132301867226@1813 15e8cca8-e42c-11de-a347-f34a4f72eb7d

pombreda/syzygy,Eloston/syzygy,supriyantomaftuh/syzygy,supriyantomaftuh/syzygy,google/syzygy,supriyantomaftuh/syzygy,google/syzygy,sebmarchand/syzygy,ericmckean/syzygy,google/syzygy,ericmckean/syzygy,pombreda/syzygy,sebmarchand/syzygy,Eloston/syzygy,pombreda/syzygy,google/syzygy,pombreda/syzygy,pombreda/syzygy,sebmarchand/syzygy,sebmarchand/syzygy,wangming28/syzygy,supriyantomaftuh/syzygy,wangming28/syzygy,sebmarchand/syzygy,ericmckean/syzygy,ericmckean/syzygy,ericmckean/syzygy,wangming28/syzygy,wangming28/syzygy