Rename and refactor DownloadCurrentBuild and related functions.

Rename and refactor DownloadCurrentBuild and related functions.

This CL renames a couple functions in order to try to more accurately reflect what they do:
  BuildCurrentRevision -> _ObtainBuild
  DownloadCurrentBuild -> _DownloadAndUnzipBuild

This CL breaks two sub-functions out of DownloadCurrentBuild:
  _WaitForBuildDownload
  _UnzipAndMoveBuildProducts

Note: Later, I plan to replace _GetBuildArchiveForRevision with fetch_build.FetchBuild, and possibly change _UnzipAndMoveBuildProducts so that it doesn't do unzipping, since unzipping is done in fetch_build.FetchBuild. Either that, or make it so that unzipping isn't done in that function.

BUG=

Committed: https://crrev.com/472793788cbb265ce69176d0940922262c0649c5
Cr-Commit-Position: refs/heads/master@{#301029}

[qyearsley, 2014-10-18 01:15:20]

qyearsley@chromium.org changed reviewers:
+ prasadv@chromium.org

[qyearsley, 2014-10-18 01:17:01]

Hey guys, this CL is supposed to break up DownloadCurrentBuild in order to make
it simpler to change it to use fetch_build.FetchBuild.

Any suggestions?

[prasadv, 2014-10-23 22:55:46]

lgtm

[qyearsley, 2014-10-24 01:09:59]

The CQ bit was checked by qyearsley@chromium.org

[commit-bot: I haz the power, 2014-10-24 01:11:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/664793002/60001

[commit-bot: I haz the power, 2014-10-24 02:04:47]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2014-10-24 02:05:22]

Patchset 4 (id:??) landed as
https://crrev.com/472793788cbb265ce69176d0940922262c0649c5
Cr-Commit-Position: refs/heads/master@{#301029}