[pdf] Defer page unloading in JS callback.

[pdf] Defer page unloading in JS callback.

One of the callbacks from PDFium JavaScript into the embedder is to get the
current page number. In Chromium, this will trigger a call to
CalculateMostVisiblePage that method will determine the visible pages and unload
any non-visible pages. But, if the originating JS is on a non-visible page
we'll delete the page and annotations associated with that page. This will
cause issues as we are currently working with those objects when the JavaScript
returns.

This Cl defers the page unloading triggered by getting the most visible page
until the next event is handled by the Chromium embedder.

BUG=chromium:653090
Committed: https://crrev.com/bf6a6765d44b09c64b8c75d749efb84742a250e7
Cr-Commit-Position: refs/heads/master@{#424781}

[dsinclair, 2016-10-12 14:52:43]

dsinclair@chromium.org changed reviewers:
+ raymes@chromium.org, thestig@chromium.org

[dsinclair, 2016-10-12 14:52:44]

PTAL.

[dsinclair, 2016-10-12 14:52:55]

The CQ bit was checked by dsinclair@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-12 14:53:06]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-12 15:36:15]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-12 15:36:15]

Dry run: This issue passed the CQ dry run.

[Lei Zhang, 2016-10-12 17:28:04]

lgtm

[dsinclair, 2016-10-12 17:29:06]

The CQ bit was checked by dsinclair@chromium.org

[commit-bot: I haz the power, 2016-10-12 17:29:34]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-12 17:37:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-12 17:49:45]

Description was changed from

==========
[pdf] Defer page unloading in JS callback.

One of the callbacks from PDFium JavaScript into the embedder is to get the
current page number. In Chromium, this will trigger a call to
CalculateMostVisiblePage that method will determine the visible pages and unload
any non-visible pages. But, if the originating JS is on a non-visible page
we'll delete the page and annotations associated with that page. This will
cause issues as we are currently working with those objects when the JavaScript
returns.

This Cl defers the page unloading triggered by getting the most visible page
until the next event is handled by the Chromium embedder.

BUG=chromium:653090
==========

to

==========
[pdf] Defer page unloading in JS callback.

One of the callbacks from PDFium JavaScript into the embedder is to get the
current page number. In Chromium, this will trigger a call to
CalculateMostVisiblePage that method will determine the visible pages and unload
any non-visible pages. But, if the originating JS is on a non-visible page
we'll delete the page and annotations associated with that page. This will
cause issues as we are currently working with those objects when the JavaScript
returns.

This Cl defers the page unloading triggered by getting the most visible page
until the next event is handled by the Chromium embedder.

BUG=chromium:653090

Committed: https://crrev.com/bf6a6765d44b09c64b8c75d749efb84742a250e7
Cr-Commit-Position: refs/heads/master@{#424781}
==========

[commit-bot: I haz the power, 2016-10-12 17:49:46]

Patchset 1 (id:??) landed as
https://crrev.com/bf6a6765d44b09c64b8c75d749efb84742a250e7
Cr-Commit-Position: refs/heads/master@{#424781}