Make TextDecoration an enum class.

Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly as needed.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=684966
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2845773002
Cr-Commit-Position: refs/heads/master@{#471219}
Committed: https://chromium.googlesource.com/chromium/src/+/9dc275c518d70c4fb4652fdfb5b908d060b53296

[shend, 2017-04-26 23:01:18]

Description was changed from

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=628043
==========

to

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=628043
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[shend, 2017-04-26 23:02:26]

Description was changed from

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=628043
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly as needed.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=628043
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[shend, 2017-04-26 23:02:46]

shend@chromium.org changed reviewers:
+ bugsnash@chromium.org

[shend, 2017-04-26 23:02:47]

Hi Bugs, PTAL

[Bugs Nash, 2017-04-27 00:02:23]

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/style/ComputedStyle.cpp (right):

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/style/ComputedStyle.cpp:1716: TextDecoration
decorations = TextDecoration::kNone;
yass

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/style/ComputedStyleConstants.h (right):

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/style/ComputedStyleConstants.h:273: inline bool
EnumHasFlags(TextDecoration v, TextDecoration mask) {
If this function is only going to be used for TextDecoration then rename to
TextDecorationHasFlags. If other types of enums will need the same functionality
then make this a template.

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/style/ComputedStyleConstants.h:276:
TextDecoration::kNone;
I don't think TextDecoration::kNone is exactly what you're wanting to compare to
here (although it happens to also be 0 and will work). I would find this more
readable if it was left as unsigned and compared to 0. But get a second opinion
here.

return static_cast<unsigned>(v) & static_cast<unsigned>(mask))

[shend, 2017-04-27 00:27:03]

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

[shend, 2017-04-27 00:27:34]

Addressed comments, PTAL again :)

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/style/ComputedStyle.cpp (right):

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/style/ComputedStyle.cpp:1716: TextDecoration
decorations = TextDecoration::kNone;
On 2017/04/27 at 00:02:23, Bugs Nash wrote:
> yass

yes

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/style/ComputedStyleConstants.h (right):

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/style/ComputedStyleConstants.h:273: inline bool
EnumHasFlags(TextDecoration v, TextDecoration mask) {
On 2017/04/27 at 00:02:23, Bugs Nash wrote:
> If this function is only going to be used for TextDecoration then rename to
TextDecorationHasFlags. If other types of enums will need the same functionality
then make this a template.

Certain other enums will need this as well. I will make this a template.

https://codereview.chromium.org/2845773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/style/ComputedStyleConstants.h:276:
TextDecoration::kNone;
On 2017/04/27 at 00:02:23, Bugs Nash wrote:
> I don't think TextDecoration::kNone is exactly what you're wanting to compare
to here (although it happens to also be 0 and will work). I would find this more
readable if it was left as unsigned and compared to 0. But get a second opinion
here.
> 
> return static_cast<unsigned>(v) & static_cast<unsigned>(mask))

Done.

[commit-bot: I haz the power, 2017-04-27 00:27:34]

Dry run: CQ is trying da patch.

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

[shend, 2017-04-27 00:32:00]

Description was changed from

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly as needed.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=628043
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly as needed.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=684966
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[Bugs Nash, 2017-04-27 00:53:55]

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp:12: :
lines_(static_cast<unsigned>(line)), style_(style), color_(color) {}
Hm. I think this would be better changes to TextDecoration type in
AppliedTextDecoration

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/ComputedStyle.h (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/ComputedStyle.h:1505: SET_VAR(visual_data_,
text_decoration, static_cast<unsigned>(v));
as above, I would store this as a TextDecoration on StyleVisualData. As that one
is used in many places though happy for it to be a todo in this patch and
changed in a separate patch

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/ComputedStyleConstants.h (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/ComputedStyleConstants.h:266: inline
TextDecoration operator|(TextDecoration a, TextDecoration b) {
ew c++ wat

[shend, 2017-04-27 01:09:17]

Addressed comments, PTAL again?

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp:12: :
lines_(static_cast<unsigned>(line)), style_(style), color_(color) {}
On 2017/04/27 at 00:53:54, Bugs Nash wrote:
> Hm. I think this would be better changes to TextDecoration type in
AppliedTextDecoration

Hmm, I don't think we can store it as TextDecoration because it's being stored
as an unsigned for bitfield packing.

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/ComputedStyle.h (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/ComputedStyle.h:1505: SET_VAR(visual_data_,
text_decoration, static_cast<unsigned>(v));
On 2017/04/27 at 00:53:54, Bugs Nash wrote:
> as above, I would store this as a TextDecoration on StyleVisualData. As that
one is used in many places though happy for it to be a todo in this patch and
changed in a separate patch

Same reasoning as above, we need to pack text_decoration.

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/ComputedStyleConstants.h (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/ComputedStyleConstants.h:266: inline
TextDecoration operator|(TextDecoration a, TextDecoration b) {
On 2017/04/27 at 00:53:55, Bugs Nash wrote:
> ew c++ wat

lol

[Bugs Nash, 2017-04-27 01:59:31]

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp (right):

https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp:12: :
lines_(static_cast<unsigned>(line)), style_(style), color_(color) {}
On 2017/04/27 at 01:09:17, shend wrote:
> On 2017/04/27 at 00:53:54, Bugs Nash wrote:
> > Hm. I think this would be better changes to TextDecoration type in
AppliedTextDecoration
> 
> Hmm, I don't think we can store it as TextDecoration because it's being stored
as an unsigned for bitfield packing.

would changing the type of TextDecoration from the default int to unsigned solve
that problem?

[shend, 2017-04-27 02:03:59]

On 2017/04/27 at 01:59:31, bugsnash wrote:
>
https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp (right):
> 
>
https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp:12: :
lines_(static_cast<unsigned>(line)), style_(style), color_(color) {}
> On 2017/04/27 at 01:09:17, shend wrote:
> > On 2017/04/27 at 00:53:54, Bugs Nash wrote:
> > > Hm. I think this would be better changes to TextDecoration type in
AppliedTextDecoration
> > 
> > Hmm, I don't think we can store it as TextDecoration because it's being
stored as an unsigned for bitfield packing.
> 
> would changing the type of TextDecoration from the default int to unsigned
solve that problem?

well, this patch already makes the underlying type of TextDecoration an
unsigned. The problem is enum classes don't implicitly convert to their
underlying type, so we need those casts. Theoretically we could make the type of
the bitfield TextDecoration, but apparently that makes packing weird on Windows
(sashab@ knows more about this).

[Bugs Nash, 2017-04-27 02:09:26]

On 2017/04/27 at 02:03:59, shend wrote:
> On 2017/04/27 at 01:59:31, bugsnash wrote:
> >
https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
> > File third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp (right):
> > 
> >
https://codereview.chromium.org/2845773002/diff/20001/third_party/WebKit/Sour...
> > third_party/WebKit/Source/core/style/AppliedTextDecoration.cpp:12: :
lines_(static_cast<unsigned>(line)), style_(style), color_(color) {}
> > On 2017/04/27 at 01:09:17, shend wrote:
> > > On 2017/04/27 at 00:53:54, Bugs Nash wrote:
> > > > Hm. I think this would be better changes to TextDecoration type in
AppliedTextDecoration
> > > 
> > > Hmm, I don't think we can store it as TextDecoration because it's being
stored as an unsigned for bitfield packing.
> > 
> > would changing the type of TextDecoration from the default int to unsigned
solve that problem?
> 
> well, this patch already makes the underlying type of TextDecoration an
unsigned. The problem is enum classes don't implicitly convert to their
underlying type, so we need those casts. Theoretically we could make the type of
the bitfield TextDecoration, but apparently that makes packing weird on Windows
(sashab@ knows more about this).


hm, ok. lgtm then with the caveat that you get someone who understands the bit
packing weirdness to review

[commit-bot: I haz the power, 2017-04-27 02:33:24]

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

[commit-bot: I haz the power, 2017-04-27 02:33:25]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[shend, 2017-04-27 03:38:23]

shend@chromium.org changed reviewers:
+ alancutter@chromium.org

[shend, 2017-04-27 03:38:24]

Hi Alan, PTAL

[Eric Willigers, 2017-05-05 04:59:03]

ericwilligers@chromium.org changed reviewers:
+ ericwilligers@chromium.org

[Eric Willigers, 2017-05-05 04:59:04]

lgtm

[shend, 2017-05-08 06:00:36]

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

[commit-bot: I haz the power, 2017-05-08 06:01:04]

Dry run: CQ is trying da patch.

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

[shend, 2017-05-08 06:01:09]

shend@chromium.org changed reviewers:
+ aboxhall@chromium.org
- alancutter@chromium.org

[shend, 2017-05-08 06:01:09]

Hi Alice, PTAL :)

[shend, 2017-05-08 06:01:27]

On 2017/05/08 at 06:01:09, shend wrote:
> Hi Alice, PTAL :)

* for OWNERS on accessibility

[commit-bot: I haz the power, 2017-05-08 06:18:19]

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

[commit-bot: I haz the power, 2017-05-08 06:18:20]

Dry run: Try jobs failed on following builders:
  cast_shell_android on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/cast_shell_a...)

[shend, 2017-05-08 07:56:02]

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

[commit-bot: I haz the power, 2017-05-08 07:56:23]

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, 2017-05-08 09:49:02]

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

[commit-bot: I haz the power, 2017-05-08 09:49:04]

Dry run: This issue passed the CQ dry run.

[dmazzoni, 2017-05-08 20:04:12]

dmazzoni@chromium.org changed reviewers:
+ dmazzoni@chromium.org

[dmazzoni, 2017-05-08 20:04:13]

lgtm for accessibility

Feel free to TBR for trivial changes like this
whenever a core owner has approved the change.

[shend, 2017-05-08 23:49:15]

shend@chromium.org changed reviewers:
- aboxhall@chromium.org

[shend, 2017-05-08 23:49:38]

On 2017/05/08 at 20:04:13, dmazzoni wrote:
> lgtm for accessibility
> 
> Feel free to TBR for trivial changes like this
> whenever a core owner has approved the change.

Ah, thanks for the tip!

[shend, 2017-05-08 23:56:40]

shend@chromium.org changed reviewers:
+ alancutter@chromium.org

[alancutter (OOO until 2018), 2017-05-09 00:11:45]

lgtm

[shend, 2017-05-09 04:13:12]

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

[commit-bot: I haz the power, 2017-05-09 04:14:16]

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, 2017-05-09 04:26:50]

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

[commit-bot: I haz the power, 2017-05-09 04:26:51]

Dry run: Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[shend, 2017-05-09 06:00:12]

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

[commit-bot: I haz the power, 2017-05-09 06:00:35]

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, 2017-05-09 08:59:16]

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

[commit-bot: I haz the power, 2017-05-09 08:59:17]

Dry run: This issue passed the CQ dry run.

[shend, 2017-05-11 23:20:13]

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

[commit-bot: I haz the power, 2017-05-11 23:21:24]

Dry run: CQ is trying da patch.

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

[shend, 2017-05-11 23:22:33]

The CQ bit was unchecked by shend@chromium.org

[shend, 2017-05-11 23:25:04]

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

[commit-bot: I haz the power, 2017-05-11 23:26:47]

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, 2017-05-12 01:48:16]

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

[commit-bot: I haz the power, 2017-05-12 01:48:17]

Dry run: This issue passed the CQ dry run.

[shend, 2017-05-12 04:18:16]

The CQ bit was checked by shend@chromium.org

[shend, 2017-05-12 04:18:17]

The patchset sent to the CQ was uploaded after l-g-t-m from
bugsnash@chromium.org, ericwilligers@chromium.org, dmazzoni@chromium.org,
alancutter@chromium.org
Link to the patchset: https://codereview.chromium.org/2845773002/#ps120001
(title: "Rebase")

[commit-bot: I haz the power, 2017-05-12 04:18:34]

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, 2017-05-12 04:24:09]

CQ is committing da patch.

Bot data: {"patchset_id": 120001, "attempt_start_ts": 1494562696906300,
"parent_rev": "4696e5fcb504bcaf727dd2429242c7eb67c4cc3a", "commit_rev":
"9dc275c518d70c4fb4652fdfb5b908d060b53296"}

[commit-bot: I haz the power, 2017-05-12 04:24:22]

Description was changed from

==========
Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly as needed.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=684966
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
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to

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Make TextDecoration an enum class.

This patch makes TextDecoration an enum class for better type safety.
However, TextDecoration is a bit flag, so it is often used with bitwise
operators. Enum classes do not have bitwise operators by default, so we
define our own explicitly as needed.

Furthermore, a lot of code involves testing if a bit is set/active in a
TextDecoration. Previously, we could do something like:

if (text_decoration & TextDecoration::kUnderline)

to check if underline is applied. This worked because TextDecoration
could be implicitly converted to a bool. However, enum classes cannot.
With an enum class, it is more verbose and unintuitive:

if ((text_decoration & TextDecoration::kUnderline) !=
    TextDecoration::kNone)

Hence, we also provide a helper function called EnumHasFlags that
performs this check:

if (EnumHasFlags(text_decoration, TextDecoration::kUnderline))

BUG=684966
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2845773002
Cr-Commit-Position: refs/heads/master@{#471219}
Committed:
https://chromium.googlesource.com/chromium/src/+/9dc275c518d70c4fb4652fdfb5b9...
==========

[commit-bot: I haz the power, 2017-05-12 04:24:24]

Committed patchset #7 (id:120001) as
https://chromium.googlesource.com/chromium/src/+/9dc275c518d70c4fb4652fdfb5b9...