Revert 228448 "Refactoring: Move MessagePort-related IPCs and ha..."

> Refactoring: Move MessagePort-related IPCs and handling them away from Worker-related classes.
> 
> MessagePorts can also be used by non-workers.
> 
> This is part of a series of changes to fix cross-process MessagePorts. This CL
> contains no functional changes.
> 
> BUG=278336
> 
> Review URL: https://codereview.chromium.org/25299002

TBR=marja@chromium.org

Review URL: https://codereview.chromium.org/27192002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228455 0039d316-1c4b-4281-b951-d872f2087c98
Revert 228211 "Move renderer plugin code into a new component."

There is an error in the ChromePluginPlaceholder destructor
causing pointers to it to be left around after it is freed.
Fix will follow, but reverting for now.

BUG=306815,306803
> Move renderer plugin code into a new component.
> 
> Android Webview needs to use some of the renderer plugin code, however
> this code is currently in chrome. This commit moves the parts of this
> code that don't depend on the rest of chrome into a new component.
> 
> BUG=283713
> 
> Review URL: https://codereview.chromium.org/23606022

TBR=aberent@chromium.org

Review URL: https://codereview.chromium.org/26781004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228456 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228456