Reland of Add channel-specific product logo to chrome://help

Reland of Add channel-specific product logo to chrome://help (patchset #1 id:1 of https://codereview.chromium.org/1280033002/ )

Reason for revert:
Official build bots were all happy with the change --- suspect the issue was a local config problem (such as not updating src-internal).

Original issue's description:
> Revert of Add channel-specific product logo to chrome://help (patchset #3 id:40001 of https://codereview.chromium.org/1269383005/ )
>
> Reason for revert:
> Reverting due to missing files.  See comments in cl:
> https://codereview.chromium.org/1269383005/
>
> Original issue's description:
> > Add channel-specific product logo to chrome://help
> >
> > BUG=511000
> >
> > Committed: https://crrev.com/9836302ea4ffb887ce6ffa597c1ee5484d2f1091
> > Cr-Commit-Position: refs/heads/master@{#342183}
>
> TBR=oshima@chromium.org,dbeam@chromium.org,estade@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=511000
>
> Committed: https://crrev.com/abd20f67987aaa47bb47e61288ec92b4ab761521
> Cr-Commit-Position: refs/heads/master@{#342324}

TBR=oshima@chromium.org,dbeam@chromium.org,tommi@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=511000
Committed: https://crrev.com/43556713374f9ef0b5a5254f0a4116fe5b1c4eb3
Cr-Commit-Position: refs/heads/master@{#342369}

[Evan Stade, 2015-08-07 17:20:11]

Created Reland of Add channel-specific product logo to chrome://help

[commit-bot: I haz the power, 2015-08-07 17:20:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1279093002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1279093002/1

[commit-bot: I haz the power, 2015-08-07 17:21:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-07 17:22:27]

Patchset 1 (id:??) landed as
https://crrev.com/43556713374f9ef0b5a5254f0a4116fe5b1c4eb3
Cr-Commit-Position: refs/heads/master@{#342369}