Change logic that decides when to switch processes when crossing extension boundaries: - Add back in a check that allows switching on browser-initiated redirects (that I removed since it was unnecessary for the webstore). Turns out it is needed for legitimate cases.
Change logic that decides when to switch processes when crossing extension
boundaries:
- Add back in a check that allows switching on browser-initiated redirects
(that I removed since it was unnecessary for the webstore). Turns out it is
needed for legitimate cases.

BUG=70943
TEST=no

Review URL: http://codereview.chromium.org/6272020

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@74320 0039d316-1c4b-4281-b951-d872f2087c98

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