[extensions] added checks that function is not empty

[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty v8::Local<v8::Function> if condition in first if inside of this function is false. Then invocation of any methods on this local object will produce a crash, e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org

Committed: https://crrev.com/dedd489499fb5b7b47fdd29fef13ffaee2f42dcd
Cr-Commit-Position: refs/heads/master@{#435750}

[kozy, 2016-12-01 21:48:54]

Devlin, please take a look.
It's speculative fix of crbug.com/657561 crash.

[kozy, 2016-12-01 21:49:20]

Description was changed from

==========
[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty
v8::Local<v8::Function> if condition in first if is false. Then invocation of
any methods on this local object will produce a crash, e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org
==========

to

==========
[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty
v8::Local<v8::Function> if condition in first if inside of this function is
false. Then invocation of any methods on this local object will produce a crash,
e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org
==========

[Devlin, 2016-12-01 22:09:47]

lgtm

https://codereview.chromium.org/2546853002/diff/1/extensions/renderer/module_...
File extensions/renderer/module_system.cc (right):

https://codereview.chromium.org/2546853002/diff/1/extensions/renderer/module_...
extensions/renderer/module_system.cc:312: if (function.IsEmpty()) {
This *shouldn't* ever happen, but I wouldn't be entirely surprised if it were. 
Can we NOTREACHED here (and below)?

[kozy, 2016-12-01 22:19:25]

thanks.

https://codereview.chromium.org/2546853002/diff/1/extensions/renderer/module_...
File extensions/renderer/module_system.cc (right):

https://codereview.chromium.org/2546853002/diff/1/extensions/renderer/module_...
extensions/renderer/module_system.cc:312: if (function.IsEmpty()) {
On 2016/12/01 22:09:47, Devlin wrote:
> This *shouldn't* ever happen, but I wouldn't be entirely surprised if it were.

> Can we NOTREACHED here (and below)?

Done.

[kozy, 2016-12-01 22:19:31]

The CQ bit was checked by kozyatinskiy@chromium.org

[kozy, 2016-12-01 22:19:32]

The patchset sent to the CQ was uploaded after l-g-t-m from
rdevlin.cronin@chromium.org
Link to the patchset: https://codereview.chromium.org/2546853002/#ps20001
(title: "addressed comments")

[commit-bot: I haz the power, 2016-12-01 22:20:07]

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, 2016-12-01 23:06:58]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1480630771957570,
"parent_rev": "f20510c77a8712093b5601c53afaf98d196d1d75", "commit_rev":
"5267b0efb4c07adb47390f9819197c75097859ac"}

[commit-bot: I haz the power, 2016-12-01 23:08:19]

Description was changed from

==========
[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty
v8::Local<v8::Function> if condition in first if inside of this function is
false. Then invocation of any methods on this local object will produce a crash,
e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org
==========

to

==========
[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty
v8::Local<v8::Function> if condition in first if inside of this function is
false. Then invocation of any methods on this local object will produce a crash,
e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org
==========

[commit-bot: I haz the power, 2016-12-01 23:08:20]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-12-01 23:10:08]

Description was changed from

==========
[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty
v8::Local<v8::Function> if condition in first if inside of this function is
false. Then invocation of any methods on this local object will produce a crash,
e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org
==========

to

==========
[extensions] added checks that function is not empty

ModuleSystem::GetModuleFunction function can return empty
v8::Local<v8::Function> if condition in first if inside of this function is
false. Then invocation of any methods on this local object will produce a crash,
e.g. crbug.com/657561.

BUG=657561
R=rdevlin.cronin@chromium.org

Committed: https://crrev.com/dedd489499fb5b7b47fdd29fef13ffaee2f42dcd
Cr-Commit-Position: refs/heads/master@{#435750}
==========

[commit-bot: I haz the power, 2016-12-01 23:10:09]

Patchset 2 (id:??) landed as
https://crrev.com/dedd489499fb5b7b47fdd29fef13ffaee2f42dcd
Cr-Commit-Position: refs/heads/master@{#435750}