Revert of Significantly cleans up the ImageWriter Operation class and subclasses. (https://codereview.chromium.org/149313003/)

Reason for revert:
Broke ASAN bots.

http://build.chromium.org/p/chromium.memory/builders/Linux%20ASAN%20Tests%20%282%29/builds/23085/steps/unit_tests/logs/DownloadFile

Original issue's description:
> Significantly cleans up the ImageWriter Operation class and subclasses.
> 
> * Moved Operations to be in CPS for stage isolation.
> * Updates unit tests to use isolated stages.
> * Adds unit tests for uncovered stages.
> * Cleans up temporary file handling.
> * Removes unnecessary and redundant code (CompareFiles, ImageReader).
> * Fixes bug with verification progress updates.
> * All .zip files now unzipped before burning.
> * All non-.zip files not unzipped before burning.
> * Removes unnecessary complexity, e.g. unnecessary scoped_ptrs.
> 
> BUG=292956
> BUG=337883
> BUG=335404
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251704

TBR=tbarzic@chromium.org,haven@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=292956

Review URL: https://codereview.chromium.org/170123002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251729 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251729