Do not expose is_null API for time values in Blink

Do not expose is_null API for time values in Blink

base::Time and base::TimeTicks interfaces expose a is_null() method. Unfortunately
in current implementation is_null() == is_zero() which means that it is possible
to write code that produces valid zero time but is confused with null time.
So depending on this API can lead to brittle and buggy code. There is also a desire 
to eventually get rid of |is_null()| in base/ interface.


Given above we shouldn't depend on this behavior in Blink. Any code that needs to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680
Review-Url: https://codereview.chromium.org/2656843003
Cr-Commit-Position: refs/heads/master@{#448023}
Committed: https://chromium.googlesource.com/chromium/src/+/a0651393fc46e6637ac0a5bc29c816c3f4ee9088

[majidvp, 2017-01-25 16:38:16]

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

[commit-bot: I haz the power, 2017-01-25 16:38:27]

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

[majidvp, 2017-01-25 16:44:24]

Description was changed from

==========
Do not expose null time concept in Blink

base::Time and base::TimeTicks interfaces have is_null() method. Unfortunately
is_null() == is_zero() in the implementation which means that it is possible
to write code that produces valid zero time but is confused with null time.

We don't need to depend on this behavior in Blink. Any code that needs to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680
==========

to

==========
Do not expose is_null API for time values in Blink

base::Time and base::TimeTicks interfaces expose a is_null() method.
Unfortunately
in current implementation is_null() == is_zero() which means that it is possible
to write code that produces valid zero time but is confused with null time.
So depending on this API can lead to brittle and buggy code. There is also a
desire 
to eventually get rid of |is_null()| in base/ interface.


Given abode we shouldn't depend on this behavior in Blink. Any code that needs
to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680
==========

[commit-bot: I haz the power, 2017-01-25 18:40:00]

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

[commit-bot: I haz the power, 2017-01-25 18:40:01]

Dry run: This issue passed the CQ dry run.

[majidvp, 2017-01-25 18:41:53]

majidvp@chromium.org changed reviewers:
+ esprehn@chromium.org

[esprehn, 2017-02-01 05:24:29]

Description was changed from

==========
Do not expose is_null API for time values in Blink

base::Time and base::TimeTicks interfaces expose a is_null() method.
Unfortunately
in current implementation is_null() == is_zero() which means that it is possible
to write code that produces valid zero time but is confused with null time.
So depending on this API can lead to brittle and buggy code. There is also a
desire 
to eventually get rid of |is_null()| in base/ interface.


Given abode we shouldn't depend on this behavior in Blink. Any code that needs
to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680
==========

to

==========
Do not expose is_null API for time values in Blink

base::Time and base::TimeTicks interfaces expose a is_null() method.
Unfortunately
in current implementation is_null() == is_zero() which means that it is possible
to write code that produces valid zero time but is confused with null time.
So depending on this API can lead to brittle and buggy code. There is also a
desire 
to eventually get rid of |is_null()| in base/ interface.


Given above we shouldn't depend on this behavior in Blink. Any code that needs
to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680
==========

[esprehn, 2017-02-01 05:25:20]

lgtm

https://codereview.chromium.org/2656843003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/input/EventHandler.cpp (right):

https://codereview.chromium.org/2656843003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/input/EventHandler.cpp:1667:
m_gestureManager->getLastShowPressTimestamp()) {
getLastShowPressTimestamp() I suppose is cheap enough to call twice here?

[majidvp, 2017-02-03 15:42:27]

https://codereview.chromium.org/2656843003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/input/EventHandler.cpp (right):

https://codereview.chromium.org/2656843003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/input/EventHandler.cpp:1667:
m_gestureManager->getLastShowPressTimestamp()) {
On 2017/02/01 05:25:20, esprehn wrote:
> getLastShowPressTimestamp() I suppose is cheap enough to call twice here?

It is cheap. Just a plain data member access.

[majidvp, 2017-02-03 15:42:32]

The CQ bit was checked by majidvp@chromium.org

[commit-bot: I haz the power, 2017-02-03 15:42:48]

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, 2017-02-03 18:06:43]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1486136552536920, "parent_rev":
"a870361a9f6f66ebf3618418cd3759058c844dd1", "commit_rev":
"a0651393fc46e6637ac0a5bc29c816c3f4ee9088"}

[commit-bot: I haz the power, 2017-02-03 18:07:15]

Description was changed from

==========
Do not expose is_null API for time values in Blink

base::Time and base::TimeTicks interfaces expose a is_null() method.
Unfortunately
in current implementation is_null() == is_zero() which means that it is possible
to write code that produces valid zero time but is confused with null time.
So depending on this API can lead to brittle and buggy code. There is also a
desire 
to eventually get rid of |is_null()| in base/ interface.


Given above we shouldn't depend on this behavior in Blink. Any code that needs
to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680
==========

to

==========
Do not expose is_null API for time values in Blink

base::Time and base::TimeTicks interfaces expose a is_null() method.
Unfortunately
in current implementation is_null() == is_zero() which means that it is possible
to write code that produces valid zero time but is confused with null time.
So depending on this API can lead to brittle and buggy code. There is also a
desire 
to eventually get rid of |is_null()| in base/ interface.


Given above we shouldn't depend on this behavior in Blink. Any code that needs
to have
a "null" or "invalid" time value can use WTF::Optional<WTF::Time> instead which
is more readable and explicit.

BUG=625680

Review-Url: https://codereview.chromium.org/2656843003
Cr-Commit-Position: refs/heads/master@{#448023}
Committed:
https://chromium.googlesource.com/chromium/src/+/a0651393fc46e6637ac0a5bc29c8...
==========

[commit-bot: I haz the power, 2017-02-03 18:07:16]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/a0651393fc46e6637ac0a5bc29c8...