Revert of DevTools: remove dependency of most agents on InspectorPageAgent

Revert of DevTools: remove dependency of most agents on InspectorPageAgent (patchset #6 id:100001 of https://codereview.chromium.org/1092123004/)

Reason for revert:
Reverting as a possible cause of issue 482468
BUG=482468
Original issue's description:
> DevTools: remove dependency of most agents on InspectorPageAgent
> 
> - let agents keep inspected frame directly rather than fetch it
>     from InspectorPageAgent::inspectedFrame();
> - get frames from InspectorIdentifiers<LocalFrame>, but check it
>     belongs to inspected page;
> 
> BUG=480341
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=194592

TBR=dgozman@chromium.org,pfeldman@chromium.org,yurys@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=480341
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=194801

[caseq, 2015-05-01 10:43:03]

Created Revert of DevTools: remove dependency of most agents on
InspectorPageAgent

[commit-bot: I haz the power, 2015-05-01 10:43:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1118963002/1

[commit-bot: I haz the power, 2015-05-01 10:43:49]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=194801