Revert r276792 - "Hook PushMessagingMessageFilter up to GCMDriver"

Revert r276792 - "Hook PushMessagingMessageFilter up to GCMDriver"

This change caused the sole push_messaging layout test to fail :(.

> Hook PushMessagingMessageFilter up to GCMDriver
>
> Add plumbing for registration from push service-agnostic content layer
> to GCMDriver in chrome layer.
>
> To achieve this, GCMProfileService owns an implementation of a new
> PushMessagingService class, which can be used from the content layer.
>
> Based on mvanouwerkerk's prototype in https://codereview.chromium.org/186023002, but significantly refactored.
>
> BUG=350384
> TBR=benm@chromium.org

TBR=johnme@chromium.org
BUG=350384
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276834

[Dirk Pranke, 2014-06-12 22:44:58]

Committed patchset #1 manually as r276834 (presubmit successful).

[Dirk Pranke, 2014-06-12 23:02:45]

Links to a representative failure:

http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux/builds/32769
https://storage.googleapis.com/chromium-layout-test-archives/WebKit_Linux/327...

(the test times out).