Refactor http cache removing from a StoragePartition into separate class:

Refactor http cache removing from a StoragePartition into separate class:
  StoragePartitionHttpCacheDataRemover.

This will enable us to to clear http cache from a StoragePartition from
  chrome/ layer. <webview>s with their own storage partitions can use
  this to clear patitions' cache.

This will be used to implement clear cache for <webview>, complete
  CL is: https://chromiumcodereview.appspot.com/1021073002/

BUG=406437
Test=None, internal only change.

Committed: https://crrev.com/044f3ca9e0eb0dc89ed529ef1fd7c0d20534b95d
Cr-Commit-Position: refs/heads/master@{#322428}

[lazyboy, 2015-03-26 16:33:09]

lazyboy@chromium.org changed reviewers:
+ mkwst@chromium.org

[lazyboy, 2015-03-26 16:33:09]

FYI, refactored from
https://chromiumcodereview.appspot.com/1021073002/

[Mike West, 2015-03-26 16:37:25]

LGTM, assuming the bots are happy.

[lazyboy, 2015-03-26 18:17:56]

The CQ bit was checked by lazyboy@chromium.org

[commit-bot: I haz the power, 2015-03-26 18:18:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1033013003/1

[commit-bot: I haz the power, 2015-03-26 18:22:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-26 18:23:57]

Patchset 1 (id:??) landed as
https://crrev.com/044f3ca9e0eb0dc89ed529ef1fd7c0d20534b95d
Cr-Commit-Position: refs/heads/master@{#322428}