Fix a failing DCHECK in MetricsLogManager.
Fix a failing DCHECK in MetricsLogManager.

StoreStagedLogAsUnsent can be called with a NULL staged_log_.
(when compressed_staged_log_text_ is not empty). Modifying the
expectation to reflect that.

BUG=
TEST=


Review URL: http://codereview.chromium.org/8729015

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@111999 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,ropik/chromium,gavinp/chromium