Block HTML Imports from loading when inserted via innerHTML.

Block HTML Imports from loading when inserted via innerHTML.

This matches the 'already started' behavior of '<script>' (which also
does not execute in 'innerHTML'.

BUG=416036

[Mike West, 2016-02-05 15:15:42]

mkwst@chromium.org changed reviewers:
+ dglazkov@chromium.org, kouhei@chromium.org

[Mike West, 2016-02-05 15:15:42]

Hello, kouhei@! Would you mind reviewing this small change to the parser? I
talked with dglazkov@ earlier in the week about the change itself, so I'm
confident that the behavior is what we want, but I haven't done much work in the
parser at all, so I'd appreciate your input on the approach.

Thanks!

-mike

[dglazkov, 2016-02-05 18:25:54]

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/html/HTMLLinkElement.h (right):

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/html/HTMLLinkElement.h:136: static
PassRefPtrWillBeRawPtr<HTMLLinkElement> create(Document&, bool createdByParser,
bool alreadyStarted = false);
Can we use an enum bere?

https://www.chromium.org/blink/coding-style#TOC-Names

"Prefer enums to bools on function parameters if callers are likely to be
passing constants, since named constants are easier to read at the call site. An
exception to this rule is a setter function, where the name of the function
already makes clear what the boolean is."

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/html/HTMLLinkElement.h:189:
HTMLLinkElement(Document&, bool createdByParser, bool alreadyStarted);
alreadyStarted is not clear in this context. What had started?

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.cpp
(right):

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.cpp:634:
insertLinkElement(token);
Would it be better to just split linkTag from
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

[kouhei (in TOK), 2016-02-08 01:00:31]

QQ: Do we only want to disable "imports" from innerHTML?
<link> tag is used for variety of purposes like CSS, preload, and prefetch.

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/LayoutTe...
File
third_party/WebKit/LayoutTests/http/tests/htmlimports/import-innerHTML-blocked.html
(right):

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/LayoutTe...
third_party/WebKit/LayoutTests/http/tests/htmlimports/import-innerHTML-blocked.html:15:
assert_true(null == innerLink.import, 'Import via innerHTML');
===?

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/LayoutTe...
third_party/WebKit/LayoutTests/http/tests/htmlimports/import-innerHTML-blocked.html:16:
assert_true(null != followingLink.import, 'Following import loaded');
!==?

[kouhei (in TOK), 2016-02-08 01:30:24]

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/html/HTMLLinkElement.h (right):

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/html/HTMLLinkElement.h:136: static
PassRefPtrWillBeRawPtr<HTMLLinkElement> create(Document&, bool createdByParser,
bool alreadyStarted = false);
On 2016/02/05 18:25:53, dglazkov wrote:
> Can we use an enum bere?
> 
> https://www.chromium.org/blink/coding-style#TOC-Names
> 
> "Prefer enums to bools on function parameters if callers are likely to be
> passing constants, since named constants are easier to read at the call site.
An
> exception to this rule is a setter function, where the name of the function
> already makes clear what the boolean is."

+1
I prefer extending "bool createdByParser" to enum, and appending
CreatedByFragmentParser state there.

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.cpp
(right):

https://codereview.chromium.org/1670203002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.cpp:677: const
bool parserInserted = m_parserContentPolicy !=
AllowScriptingContentAndDoNotMarkAlreadyStarted;
I'm not sure if we should respect
"AllowScriptingContentAndDoNotMarkAlreadyStarted" here.
However, after some archeology, the only code using the flag is added on the CL:
https://chromium.googlesource.com/chromium/src/+/ea2645777533e3efba4f2ab16f49...
And I don't see a good reason why the code needs to use the flag.
Let me try a CL that removes the flag entirely.