Revert of [DevTools] Make DevTools clients talk directly to DevToolsAgentHost instead of using DevToolsManage…

Revert of [DevTools] Make DevTools clients talk directly to DevToolsAgentHost instead of using DevToolsManage… (https://codereview.chromium.org/449043002/)

Reason for revert:
https://code.google.com/p/chromium/issues/detail?id=402835

Original issue's description:
> [DevTools] Make DevTools clients talk directly to DevToolsAgentHost instead of using DevToolsManager.
> 
> Previously, client used methods on DevToolsManager passing |this| to most of them.
> Instead, it should hold a scoped_refptr to inspected DevToolsAgentHost and talk
> to it directly. This creates a single clean entry point for the client, and allows
> in the future to handle browser-wide protocol messages and debug multiple hosts at once.
> 
> BUG=401073
> TBR=kalman@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288452

TBR=jam@chromium.org,kalman@chromium.org,dgozman@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=401073
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288946

[pfeldman, 2014-08-12 12:28:43]

Created Revert of [DevTools] Make DevTools clients talk directly to
DevToolsAgentHost instead of using DevToolsManage…