Remove unnecessary IndexedDB deps from content/common

Remove unnecessary IndexedDB deps from content/common

These used to be necessary for enums, but those were moved to
public/platform/WebIDBTypes.h aeons ago. It looks like
content/browser/DEPS was updated but content/common/DEPS was missed.

R=jam@chromium.org

Committed: https://crrev.com/d4e688f5aab967465b182257983d47276696d3e5
Cr-Commit-Position: refs/heads/master@{#319197}

[jsbell, 2015-03-05 00:30:46]

jam@ - please take a look?

[jam, 2015-03-05 01:47:20]

lgtm

[jsbell, 2015-03-05 02:00:39]

The CQ bit was checked by jsbell@chromium.org

[commit-bot: I haz the power, 2015-03-05 02:01:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/966463004/1

[commit-bot: I haz the power, 2015-03-05 02:39:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-05 02:40:09]

Patchset 1 (id:??) landed as
https://crrev.com/d4e688f5aab967465b182257983d47276696d3e5
Cr-Commit-Position: refs/heads/master@{#319197}