Update functionality of coverage extension.

Change If1aa25fc7237e9bb5100d2a4a8e560f0a68eba61 adds additional
functionality to the coverage extension. Mainly returning the
data file path for the 'stop' action and adding support for
generating html reports. This commit adds support for this new
functionality.

Change-Id: Icd147350d5c038f6b9c8063e77a75370eb8422e9
Merge "Update functionality of coverage extension."