Prevent TouchEvent Crash on X

Prevent TouchEvent Crash on X

When TouchEvents are copied the base::NativeEvent of the copy is set as null for
GenericEvent types, such as touchs.

Touch Release and Cancel events are set to remove a native touch id mapping upon
destruction.

This causes copied Touch Release/Cancel events to attempt to remove a mapping on
a null native event. Leading to a crash.

I've explicitly defined a copy constructor on TouchEvent to stop copied events
from attempting to remove this mapping.

TEST=EventsXTest.CopiedTouchEventNotRemovingFromNativeMapping
BUG=467102
Committed: https://crrev.com/5444194bd4e2f4dda4725169b879af6077dd240a
Cr-Commit-Position: refs/heads/master@{#321563}

[jonross, 2015-03-19 22:32:45]

Patchset #1 (id:1) has been deleted

[jonross, 2015-03-19 22:34:55]

jonross@chromium.org changed reviewers:
+ sadrul@chromium.org

[jonross, 2015-03-19 22:34:56]

Hi Sadrul,

Could you review this change? I have added a copy constructor to TouchEvent to
prevent copying the should_remove_native_touch_id_mapping_.

I've also added a test that reproduces the crash seen on device.

Thanks,
Jon

[sadrul, 2015-03-20 04:01:26]

lgtm

[jonross, 2015-03-20 11:40:11]

The CQ bit was checked by jonross@chromium.org

[commit-bot: I haz the power, 2015-03-20 11:40:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1026573002/20001

[commit-bot: I haz the power, 2015-03-20 13:13:53]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2015-03-20 13:14:33]

Patchset 1 (id:??) landed as
https://crrev.com/5444194bd4e2f4dda4725169b879af6077dd240a
Cr-Commit-Position: refs/heads/master@{#321563}