Abandon Prerender upon finalizing PrerenderHandle.

Abandon Prerender upon finalizing PrerenderHandle.

Forcefully sever the connection to the embedder upon the PrerenderHandle
becoming unreachable and unused. Otherwise we risk Prerender leaks
and renderer shutdown crashes when the embedder tries to access Blink
after it has already been shut down.

R=haraken
BUG=602227
Review URL: https://codereview.chromium.org/1872383002

Cr-Commit-Position: refs/heads/master@{#386401}
(cherry picked from commit 4224af9fbca8e40376cd4bd591fde530fb394183)

Committed: https://chromium.googlesource.com/chromium/src/+/b204d3fcfd7f0d514ad784d18d53769495ab2262

[pasko, 2016-04-26 17:12:53]

Description was changed from

==========
Abandon Prerender upon finalizing PrerenderHandle.

Forcefully sever the connection to the embedder upon the PrerenderHandle
becoming unreachable and unused. Otherwise we risk Prerender leaks
and renderer shutdown crashes when the embedder tries to access Blink
after it has already been shut down.

R=haraken
BUG=602227

Review URL: https://codereview.chromium.org/1872383002

Cr-Commit-Position: refs/heads/master@{#386401}
(cherry picked from commit 4224af9fbca8e40376cd4bd591fde530fb394183)
==========

to

==========
Abandon Prerender upon finalizing PrerenderHandle.

Forcefully sever the connection to the embedder upon the PrerenderHandle
becoming unreachable and unused. Otherwise we risk Prerender leaks
and renderer shutdown crashes when the embedder tries to access Blink
after it has already been shut down.

R=haraken
BUG=602227

Review URL: https://codereview.chromium.org/1872383002

Cr-Commit-Position: refs/heads/master@{#386401}
(cherry picked from commit 4224af9fbca8e40376cd4bd591fde530fb394183)

Committed:
https://chromium.googlesource.com/chromium/src/+/b204d3fcfd7f0d514ad784d18d53...
==========

[pasko, 2016-04-26 17:12:55]

Committed patchset #1 (id:1) manually as
b204d3fcfd7f0d514ad784d18d53769495ab2262.

[haraken, 2016-04-26 17:28:42]

LGTM