I think someone needs to sit down the spec and remove all of these notImplemented() calls.

ex.

https://chromium.googlesource.com/chromium/blink/+/73deabbe706a1671a636da0b0d08818be94137b0/Source/core/html/parser/HTMLTreeBuilder.cpp#2491

We should probably mark the script started?

ex.

https://chromium.googlesource.com/chromium/blink/+/73deabbe706a1671a636da0b0d08818be94137b0/Source/core/html/parser/HTMLTreeBuilder.cpp#2507

I don't get why this one is notImplemented(), it seems to do what I expected? If we're in the initial mode and we hit a start tag we invoke this method, which sets the default compat mode, which I think is expected. I don't know what about the algorithm was never implemented... looking at the spec it says:

""
12.2.5.4.1 The "initial" insertion mode

...

Anything else
If the document is not an iframe srcdoc document, then this is a parse error; set the Document to quirks mode.

In any case, switch the insertion mode to "before html", then reprocess the token.
""

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/62d2d8f07c321e78398a12e1344773f8db169f13

commit 62d2d8f07c321e78398a12e1344773f8db169f13
Author: tkent <tkent@chromium.org>
Date: Mon Mar 28 23:28:29 2016

Replace notImplemented() in core/html/parser/ with DVLOG(1).

This is a part of the task removing notImplemented().
We can't replace notImplemented()s in core/html/parser/ with NOTIMPLEMENTED()
because they hit too frequently.

These logs are not visible by default even in Debug build.
They are visible by --vmodule flag. e.g.
  % run-webkit-tests --debug --additional-driver-flag=--vmodule=HTMLTreeBuilder=1

BUG= 596760 ,597781

Review URL: https://codereview.chromium.org/1836843002

Cr-Commit-Position: refs/heads/master@{#383605}

[modify] https://crrev.com/62d2d8f07c321e78398a12e1344773f8db169f13/third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.cpp
[modify] https://crrev.com/62d2d8f07c321e78398a12e1344773f8db169f13/third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp
[modify] https://crrev.com/62d2d8f07c321e78398a12e1344773f8db169f13/third_party/WebKit/Source/core/html/parser/HTMLTokenizer.cpp
[modify] https://crrev.com/62d2d8f07c321e78398a12e1344773f8db169f13/third_party/WebKit/Source/core/html/parser/HTMLTreeBuilder.cpp

This issue has been available for more than 365 days, and should be re-evaluated. Please re-triage this issue.
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This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

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