Initial Implementation of Iframe Attribute for Feature Policy (Part 2)

Initial Implementation of Iframe Attribute for Feature Policy (Part 2)

Enable iframe feature policy by attributes:
  allow="feature1 feature2", allowfullscreen, and allowpaymentrequest.

See design doc: https://docs.google.com/a/chromium.org/document/d/1sskoBi7Ba7hLuuiJQ6VMQ1KYIGBP8Lr87hLbkF76c2I/edit?usp=sharing

Part 1: Introduce iframe allowAttr in HTMLIFrameElement::parseAttribute
and store featureNames in HTMLIFrameElement
(CL: https://codereview.chromium.org/2680083002/)

Part 2: Propagate featureNames from HTMLIFrameElement to frame owner and
remote frame owner.

Part 3: Set iframe feature policy in FrameLoader::didBeginDocument

Part 4.a: Replace implementation of allowpaymentrequest by feature policy

Part 4.b: Replace implementation of allowfullscreen by feature policy

Part 5: WebVR

BUG=682256
Review-Url: https://codereview.chromium.org/2697713003
Cr-Commit-Position: refs/heads/master@{#452087}
Committed: https://chromium.googlesource.com/chromium/src/+/fec23406245485fa37f09c3611d014b22cdd234c

[lunalu1, 2017-02-14 22:32:29]

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

[commit-bot: I haz the power, 2017-02-14 22:33:14]

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

[lunalu1, 2017-02-14 22:36:15]

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

[lunalu1, 2017-02-14 22:36:25]

Patchset #1 (id:1) has been deleted

[commit-bot: I haz the power, 2017-02-14 22:36:54]

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

[lunalu1, 2017-02-14 22:37:00]

lunalu@chromium.org changed reviewers:
+ iclelland@chromium.org

[lunalu1, 2017-02-14 22:37:01]

Hi Ian, could you please take a look at this.

Thanks

[lunalu1, 2017-02-14 22:39:53]

Description was changed from

==========
Initial Implementation of Iframe Attribute for Feature Policy (Part 2)

Enable iframe feature policy by attributes:
  allow="feature1 feature2", allowfullscreen, and allowpaymentrequest.

See design doc:
https://docs.google.com/a/google.com/document/d/1ZTuCRKNnWKQUn8gzufuRsCnjVXtP...

Part 1: Introduce iframe allowAttr in HTMLIFrameElement::parseAttribute
and store featureNames in HTMLIFrameElement
(CL: https://codereview.chromium.org/2680083002/)

Part 2: Propagate featureNames from HTMLIFrameElement to frame owner and
remote frame owner.

Part 3: Set iframe feature policy in FrameLoader::didBeginDocument

Part 4.a: Replace implementation of allowpaymentrequest by feature policy

Part 4.b: Replace implementation of allowfullscreen by feature policy

Part 5: WebVR

BUG=682256
==========

to

==========
Initial Implementation of Iframe Attribute for Feature Policy (Part 2)

Enable iframe feature policy by attributes:
  allow="feature1 feature2", allowfullscreen, and allowpaymentrequest.

See design doc:
https://docs.google.com/a/chromium.org/document/d/1sskoBi7Ba7hLuuiJQ6VMQ1KYIG...

Part 1: Introduce iframe allowAttr in HTMLIFrameElement::parseAttribute
and store featureNames in HTMLIFrameElement
(CL: https://codereview.chromium.org/2680083002/)

Part 2: Propagate featureNames from HTMLIFrameElement to frame owner and
remote frame owner.

Part 3: Set iframe feature policy in FrameLoader::didBeginDocument

Part 4.a: Replace implementation of allowpaymentrequest by feature policy

Part 4.b: Replace implementation of allowfullscreen by feature policy

Part 5: WebVR

BUG=682256
==========

[commit-bot: I haz the power, 2017-02-14 23:24:26]

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

[commit-bot: I haz the power, 2017-02-14 23:24:28]

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

[lunalu1, 2017-02-15 23:32:43]

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

[commit-bot: I haz the power, 2017-02-15 23:34:23]

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, 2017-02-15 23:41:04]

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

[commit-bot: I haz the power, 2017-02-15 23:41:05]

Dry run: Try jobs failed on following builders:
  android_arm64_dbg_recipe on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_arm6...)
  android_clang_dbg_recipe on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_clan...)
  android_cronet on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_cron...)
  android_n5x_swarming_rel on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_n5x_...)
  cast_shell_android on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/cast_shell_a...)
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[lunalu1, 2017-02-16 15:14:08]

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

[commit-bot: I haz the power, 2017-02-16 15:14:36]

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

[lunalu1, 2017-02-16 15:15:06]

Patchset #1 (id:20001) has been deleted

[iclelland, 2017-02-16 15:26:34]

This is looking really good, thanks! A couple of questions below.

https://codereview.chromium.org/2697713003/diff/40001/content/common/frame_me...
File content/common/frame_messages.h (right):

https://codereview.chromium.org/2697713003/diff/40001/content/common/frame_me...
content/common/frame_messages.h:172:
IPC_ENUM_TRAITS_MIN_MAX_VALUE(blink::WebFeaturePolicyFeature,
There's another block, at the top of this file, with all of the IPC_ENUM_TRAITS
definitions -- can you move this there?

https://codereview.chromium.org/2697713003/diff/40001/content/test/data/allow...
File content/test/data/allowed_frames.html (right):

https://codereview.chromium.org/2697713003/diff/40001/content/test/data/allow...
content/test/data/allowed_frames.html:7: cross-site iframes:
I think we should remove these labels; I don't think they're adding any value to
the test file.

https://codereview.chromium.org/2697713003/diff/40001/content/test/data/allow...
content/test/data/allowed_frames.html:10: <iframe name="frame2" id="child-2"
allow="fullscreen vibrate" src="title1.html"></iframe>
In addition to these two, I'd like to have a couple of other tests on this
attribute (I'm not sure this file is the right place, but I think so):

<iframe allow="" src="..."> (empty allow attribute)
<iframe src="..."> (no allow attribute)

To ensure that we can properly transfer and read an empty allow attribute. WDYT?

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/frame/FrameOwner.h (right):

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:55: virtual const
WebVector<WebFeaturePolicyFeature>& allowedFeatureNames()
I feel like we should rename this to allowedFeatures everywhere, since it's a
vector of features, and not just strings. Would that make sense?

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:56: const = 0;
I'm curious why this is a pure virtual method, when the exact same default
implementation needs to be used in two if its three subclasses.

Is there a reason we can't use the default implementation here, and then not
have to re-define it in DummyFrameOwner and HTMLFrameOwnerElement?

[commit-bot: I haz the power, 2017-02-16 15:59:16]

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

[commit-bot: I haz the power, 2017-02-16 15:59:17]

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

[lunalu1, 2017-02-16 20:14:06]

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

[commit-bot: I haz the power, 2017-02-16 20:15:06]

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

[lunalu1, 2017-02-16 20:16:16]

Hi Ian,

Thanks for reviewing my CL. I made some changes based on your comments.

I am not convinced to unvirtualize the allowedFeautres() method. Please see my
reasoning below.

Thanks

https://codereview.chromium.org/2697713003/diff/40001/content/common/frame_me...
File content/common/frame_messages.h (right):

https://codereview.chromium.org/2697713003/diff/40001/content/common/frame_me...
content/common/frame_messages.h:172:
IPC_ENUM_TRAITS_MIN_MAX_VALUE(blink::WebFeaturePolicyFeature,
On 2017/02/16 15:26:33, iclelland wrote:
> There's another block, at the top of this file, with all of the
IPC_ENUM_TRAITS
> definitions -- can you move this there?

Done.

https://codereview.chromium.org/2697713003/diff/40001/content/test/data/allow...
File content/test/data/allowed_frames.html (right):

https://codereview.chromium.org/2697713003/diff/40001/content/test/data/allow...
content/test/data/allowed_frames.html:7: cross-site iframes:
On 2017/02/16 15:26:33, iclelland wrote:
> I think we should remove these labels; I don't think they're adding any value
to
> the test file.

Done.

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/frame/FrameOwner.h (right):

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:55: virtual const
WebVector<WebFeaturePolicyFeature>& allowedFeatureNames()
On 2017/02/16 15:26:33, iclelland wrote:
> I feel like we should rename this to allowedFeatures everywhere, since it's a
> vector of features, and not just strings. Would that make sense?

Done.

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:56: const = 0;
On 2017/02/16 15:26:33, iclelland wrote:
> I'm curious why this is a pure virtual method, when the exact same default
> implementation needs to be used in two if its three subclasses.
> 
> Is there a reason we can't use the default implementation here, and then not
> have to re-define it in DummyFrameOwner and HTMLFrameOwnerElement?

We can use a default definition here, that just means we will have to copy the
m_allowedFeatures to here to return?
Currently virtual method is used for other attributes like allowfullscreen() and
delegatedPermissions(), which is why I followed the same pattern.

[iclelland, 2017-02-16 20:33:40]

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/frame/FrameOwner.h (right):

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:56: const = 0;
On 2017/02/16 20:16:15, loonybear wrote:
> On 2017/02/16 15:26:33, iclelland wrote:
> > I'm curious why this is a pure virtual method, when the exact same default
> > implementation needs to be used in two if its three subclasses.
> > 
> > Is there a reason we can't use the default implementation here, and then not
> > have to re-define it in DummyFrameOwner and HTMLFrameOwnerElement?
> 
> We can use a default definition here, that just means we will have to copy the
> m_allowedFeatures to here to return?
> Currently virtual method is used for other attributes like allowfullscreen()
and
> delegatedPermissions(), which is why I followed the same pattern. 

I'm just wondering whether the pattern is there for a good reason. I thought
that we could move this method:

  const WebVector<WebFeaturePolicyFeature>& allowedFeatureNames() const {
    DEFINE_STATIC_LOCAL(WebVector<WebFeaturePolicyFeature>, features, ());
    return features;
  }

into FrameOwner, and then it would be the default for things like
HTMLEmbedElement, HTMLObjectElement, HTMLFrameElement, etc. The version with
m_allowedFeatures would just be in HTMLIframeElement and RemoteFrameOwner. But
maybe there's a good reason we can't do that.

[iclelland, 2017-02-16 20:49:28]

This LGTM, thanks!

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/frame/FrameOwner.h (right):

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:56: const = 0;
On 2017/02/16 20:33:40, iclelland wrote:
> On 2017/02/16 20:16:15, loonybear wrote:
> > On 2017/02/16 15:26:33, iclelland wrote:
> > > I'm curious why this is a pure virtual method, when the exact same default
> > > implementation needs to be used in two if its three subclasses.
> > > 
> > > Is there a reason we can't use the default implementation here, and then
not
> > > have to re-define it in DummyFrameOwner and HTMLFrameOwnerElement?
> > 
> > We can use a default definition here, that just means we will have to copy
the
> > m_allowedFeatures to here to return?
> > Currently virtual method is used for other attributes like allowfullscreen()
> and
> > delegatedPermissions(), which is why I followed the same pattern. 
> 
> I'm just wondering whether the pattern is there for a good reason. I thought
> that we could move this method:
> 
>   const WebVector<WebFeaturePolicyFeature>& allowedFeatureNames() const {
>     DEFINE_STATIC_LOCAL(WebVector<WebFeaturePolicyFeature>, features, ());
>     return features;
>   }
> 
> into FrameOwner, and then it would be the default for things like
> HTMLEmbedElement, HTMLObjectElement, HTMLFrameElement, etc. The version with
> m_allowedFeatures would just be in HTMLIframeElement and RemoteFrameOwner. But
> maybe there's a good reason we can't do that.

I suppose this might be for memory savings -- if the compiler can avoid
generating a vtable for this class when all methods are pure virtual. Following
the existing pattern is fine here, I think. If we want to revisit, we can move
all of these related methods in the same CL and measure any memory regression.

[lunalu1, 2017-02-16 21:33:46]

lunalu@chromium.org changed reviewers:
+ nasko@chromium.org, pfeldman@chromium.org

[lunalu1, 2017-02-16 21:33:47]

Hi nasko@, could you please take look at the frame messages? Hi pfeldman@, could
you please look at everything else?

Thanks

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/frame/FrameOwner.h (right):

https://codereview.chromium.org/2697713003/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/FrameOwner.h:56: const = 0;
On 2017/02/16 20:33:40, iclelland wrote:
> On 2017/02/16 20:16:15, loonybear wrote:
> > On 2017/02/16 15:26:33, iclelland wrote:
> > > I'm curious why this is a pure virtual method, when the exact same default
> > > implementation needs to be used in two if its three subclasses.
> > > 
> > > Is there a reason we can't use the default implementation here, and then
not
> > > have to re-define it in DummyFrameOwner and HTMLFrameOwnerElement?
> > 
> > We can use a default definition here, that just means we will have to copy
the
> > m_allowedFeatures to here to return?
> > Currently virtual method is used for other attributes like allowfullscreen()
> and
> > delegatedPermissions(), which is why I followed the same pattern. 
> 
> I'm just wondering whether the pattern is there for a good reason. I thought
> that we could move this method:
> 
>   const WebVector<WebFeaturePolicyFeature>& allowedFeatureNames() const {
>     DEFINE_STATIC_LOCAL(WebVector<WebFeaturePolicyFeature>, features, ());
>     return features;
>   }
> 
> into FrameOwner, and then it would be the default for things like
> HTMLEmbedElement, HTMLObjectElement, HTMLFrameElement, etc. The version with
> m_allowedFeatures would just be in HTMLIframeElement and RemoteFrameOwner. But
> maybe there's a good reason we can't do that.

According to Google Style Guide
(https://google.github.io/styleguide/cppguide.html#Multiple_Inheritance), a
subclass with more than one base classes is only allowed if at most one of the
base class has an implementation. All other base classes must be pure interface
classes. 
An example in our case would be HTMLFrameOwnerElement. It has 2 base classes,
HTMLElement and FrameOwner. FrameOwner is the pure interface class here.

[lunalu1, 2017-02-16 21:44:36]

lunalu@chromium.org changed reviewers:
+ kenrb@chromium.org
- nasko@chromium.org

[lunalu1, 2017-02-16 21:44:37]

Hi kenrb@, could you please take a look at the frame messages?
Thanks

[nasko, 2017-02-16 21:50:17]

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

[nasko, 2017-02-16 21:50:18]

content/ LGTM

https://codereview.chromium.org/2697713003/diff/60001/content/common/frame_me...
File content/common/frame_messages.h (right):

https://codereview.chromium.org/2697713003/diff/60001/content/common/frame_me...
content/common/frame_messages.h:115: blink::WebFeaturePolicyFeature::NotFound,
Since the enum starts at 0, you don't need to supply MIN value.

[commit-bot: I haz the power, 2017-02-16 23:17:10]

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

[commit-bot: I haz the power, 2017-02-16 23:17:11]

Dry run: This issue passed the CQ dry run.

[kenrb, 2017-02-17 17:41:15]

ipc lgtm, % nits

https://codereview.chromium.org/2697713003/diff/60001/content/browser/site_pe...
File content/browser/site_per_process_browsertest.cc (right):

https://codereview.chromium.org/2697713003/diff/60001/content/browser/site_pe...
content/browser/site_per_process_browsertest.cc:9195: // Test iframe "allow"
attribute is propogated correctly.
nit: s/propogated/propagated

[lunalu1, 2017-02-21 16:19:32]

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

[commit-bot: I haz the power, 2017-02-21 16:20:05]

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

[pfeldman, 2017-02-21 18:27:16]

lgtm

[lunalu1, 2017-02-21 19:00:34]

The CQ bit was checked by lunalu@chromium.org

[lunalu1, 2017-02-21 19:00:34]

The patchset sent to the CQ was uploaded after l-g-t-m from kenrb@chromium.org,
iclelland@chromium.org, nasko@chromium.org
Link to the patchset: https://codereview.chromium.org/2697713003/#ps80001
(title: "Codereview: nit")

[commit-bot: I haz the power, 2017-02-21 19:00:56]

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, 2017-02-21 21:06:45]

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

[commit-bot: I haz the power, 2017-02-21 21:06:47]

Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_TIMED_OUT, no build
URL)

[lunalu1, 2017-02-21 21:30:35]

The CQ bit was checked by lunalu@chromium.org

[commit-bot: I haz the power, 2017-02-21 21:32:47]

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, 2017-02-21 22:07:28]

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

[commit-bot: I haz the power, 2017-02-21 22:07:29]

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...)

[lunalu1, 2017-02-21 22:21:33]

The CQ bit was checked by lunalu@chromium.org

[lunalu1, 2017-02-21 22:21:34]

The patchset sent to the CQ was uploaded after l-g-t-m from kenrb@chromium.org,
iclelland@chromium.org, pfeldman@chromium.org, nasko@chromium.org
Link to the patchset: https://codereview.chromium.org/2697713003/#ps100001
(title: "Update rebase")

[commit-bot: I haz the power, 2017-02-21 22:23:23]

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, 2017-02-22 00:27:50]

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

[commit-bot: I haz the power, 2017-02-22 00:27:51]

Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_TIMED_OUT, no build URL)
  chromium_presubmit on master.tryserver.chromium.linux (JOB_TIMED_OUT, no build
URL)
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_TIMED_OUT, no build URL)
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux
(JOB_TIMED_OUT, no build URL)
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_TIMED_OUT, no
build URL)
  linux_chromium_tsan_rel_ng on master.tryserver.chromium.linux (JOB_TIMED_OUT,
no build URL)

[lunalu1, 2017-02-22 02:35:58]

The CQ bit was checked by lunalu@chromium.org

[commit-bot: I haz the power, 2017-02-22 02:37:23]

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, 2017-02-22 04:40:48]

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

[commit-bot: I haz the power, 2017-02-22 04:40:50]

Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_TIMED_OUT, no build
URL)

[lunalu1, 2017-02-22 15:13:47]

The CQ bit was checked by lunalu@chromium.org

[commit-bot: I haz the power, 2017-02-22 15:13:59]

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, 2017-02-22 16:49:38]

CQ is committing da patch.

Bot data: {"patchset_id": 100001, "attempt_start_ts": 1487776427972410,
"parent_rev": "c97f87f582759e60200bc91677dfba13f87114ff", "commit_rev":
"fec23406245485fa37f09c3611d014b22cdd234c"}

[commit-bot: I haz the power, 2017-02-22 16:50:20]

Description was changed from

==========
Initial Implementation of Iframe Attribute for Feature Policy (Part 2)

Enable iframe feature policy by attributes:
  allow="feature1 feature2", allowfullscreen, and allowpaymentrequest.

See design doc:
https://docs.google.com/a/chromium.org/document/d/1sskoBi7Ba7hLuuiJQ6VMQ1KYIG...

Part 1: Introduce iframe allowAttr in HTMLIFrameElement::parseAttribute
and store featureNames in HTMLIFrameElement
(CL: https://codereview.chromium.org/2680083002/)

Part 2: Propagate featureNames from HTMLIFrameElement to frame owner and
remote frame owner.

Part 3: Set iframe feature policy in FrameLoader::didBeginDocument

Part 4.a: Replace implementation of allowpaymentrequest by feature policy

Part 4.b: Replace implementation of allowfullscreen by feature policy

Part 5: WebVR

BUG=682256
==========

to

==========
Initial Implementation of Iframe Attribute for Feature Policy (Part 2)

Enable iframe feature policy by attributes:
  allow="feature1 feature2", allowfullscreen, and allowpaymentrequest.

See design doc:
https://docs.google.com/a/chromium.org/document/d/1sskoBi7Ba7hLuuiJQ6VMQ1KYIG...

Part 1: Introduce iframe allowAttr in HTMLIFrameElement::parseAttribute
and store featureNames in HTMLIFrameElement
(CL: https://codereview.chromium.org/2680083002/)

Part 2: Propagate featureNames from HTMLIFrameElement to frame owner and
remote frame owner.

Part 3: Set iframe feature policy in FrameLoader::didBeginDocument

Part 4.a: Replace implementation of allowpaymentrequest by feature policy

Part 4.b: Replace implementation of allowfullscreen by feature policy

Part 5: WebVR

BUG=682256

Review-Url: https://codereview.chromium.org/2697713003
Cr-Commit-Position: refs/heads/master@{#452087}
Committed:
https://chromium.googlesource.com/chromium/src/+/fec23406245485fa37f09c3611d0...
==========

[commit-bot: I haz the power, 2017-02-22 16:50:22]

Committed patchset #4 (id:100001) as
https://chromium.googlesource.com/chromium/src/+/fec23406245485fa37f09c3611d0...