Fix history nav to a script-injected about:blank frame.

Fix history nav to a script-injected about:blank frame.

This CL tracks whether the browser process has an about:blank history
item for subframes during a history navigation.  If the renderer would
be staying on about:blank, it can skip asking the browser and commit
the initial about:blank page synchronously.

BUG=657896, 639842
TEST=See bug for repro steps.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
R=alexmos@chromium.org

Review URL: https://codereview.chromium.org/2438743005 .

Cr-Commit-Position: refs/heads/master@{#426880}
(cherry picked from commit 37c954965f2f221aec294a0a28dfbba1c7543f2a)

Committed: https://chromium.googlesource.com/chromium/src/+/411325b228248f37b4977f304550d42f0ce04638

[Charlie Reis, 2016-10-24 18:27:48]

Description was changed from

==========
Fix history nav to a script-injected about:blank frame.

This CL tracks whether the browser process has an about:blank history
item for subframes during a history navigation.  If the renderer would
be staying on about:blank, it can skip asking the browser and commit
the initial about:blank page synchronously.

BUG=657896, 639842
TEST=See bug for repro steps.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
R=alexmos@chromium.org

Review URL: https://codereview.chromium.org/2438743005 .

Cr-Commit-Position: refs/heads/master@{#426880}
(cherry picked from commit 37c954965f2f221aec294a0a28dfbba1c7543f2a)
==========

to

==========
Fix history nav to a script-injected about:blank frame.

This CL tracks whether the browser process has an about:blank history
item for subframes during a history navigation.  If the renderer would
be staying on about:blank, it can skip asking the browser and commit
the initial about:blank page synchronously.

BUG=657896, 639842
TEST=See bug for repro steps.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
R=alexmos@chromium.org

Review URL: https://codereview.chromium.org/2438743005 .

Cr-Commit-Position: refs/heads/master@{#426880}
(cherry picked from commit 37c954965f2f221aec294a0a28dfbba1c7543f2a)

Committed:
https://chromium.googlesource.com/chromium/src/+/411325b228248f37b4977f304550...
==========

[Charlie Reis, 2016-10-24 18:27:51]

Committed patchset #1 (id:1) manually as
411325b228248f37b4977f304550d42f0ce04638.