GuestView: Cleanup on Embedder process swap

GuestView: Cleanup on Embedder process swap

BUG=408688
Test=Launch chrome://extensions with --enable-embedded-extension-options, open SPDY options, navigate to www.google.com, the "Options: SPDY Proxy Extension Options" entry should disappear from the Task Manager.

Committed: https://crrev.com/01fcc507ca7ff1686042b237c6b853a463edcf76
Cr-Commit-Position: refs/heads/master@{#292505}

[Fady Samuel, 2014-08-28 18:46:56]

fsamuel@chromium.org changed reviewers:
+ lazyboy@chromium.org

[lazyboy, 2014-08-28 18:50:27]

lgtm

Add a Test= section to the CL describing how the behavior can be tested, thanks.

[Fady Samuel, 2014-08-28 18:53:57]

The CQ bit was checked by fsamuel@chromium.org

[commit-bot: I haz the power, 2014-08-28 18:55:21]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/fsamuel@chromium.org/514653003/1

[commit-bot: I haz the power, 2014-08-28 23:51:13]

Committed patchset #1 (id:1) as 6748658c42a6a82eb4d53f92fc94cb77a48bb7c0

[commit-bot: I haz the power, 2014-09-10 03:03:48]

Patchset 1 (id:??) landed as
https://crrev.com/01fcc507ca7ff1686042b237c6b853a463edcf76
Cr-Commit-Position: refs/heads/master@{#292505}