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merge_pr_8527

merge_pr_8527: [ES6 Module] Reflect Spec PR 2991 to make error handling deterministic
@hiroshige-g hiroshige-g tagged this 19 Dec 23:12 
Spec update: https://github.com/whatwg/html/pull/2991
V8-side change: https://chromium-review.googlesource.com/763369

Data members for errors are restructured:

Removed module script's "is errored" #concept-module-script-is-errored
  => Removed ModuleScript::IsErrored().

Removed module script's "error" #concept-module-script-error
  => Removed Modulator::GetError(), ModuleScript::CreateError(), and
     ModuleScript::CreateErrorInternal().

Removed "set the pre-instantiation error"
  #concept-module-script-set-pre-instantiation-error
  => Removed ModuleScript::SetErrorAndClearRecord().

Introduced script's "error to rethrow" #concept-script-error-to-rethrow
  => Added ModuleScript::error_to_rethrow_ and its accessors.
     Also renamed ModuleScript::preinstantiation_error_ to
     parse_error_, and added its accessors,

HTML/Blink no longer checks modules' status:

Removed references to [[Status]] and [[ErrorCompletion]] field.
  => Removed Modulator::GetRecordStatus(), ModuleScript::RecordStatus(),
     and calls to ScriptModule::ErrorCompletion().

Removed module script's "has instantiated"
  #concept-module-script-has-instantiated
  => Removed ModuleScript::HasInstantiated().

A subsequent CL will do further cleanup:
https://chromium-review.googlesource.com/802465

Error handling algorithms in the HTML spec were updated:
- #creating-a-module-script
- #run-a-module-script
- [FFPE] #finding-the-first-parse-error
- [IMSGF] #internal-module-script-graph-fetching-procedure
- [FD] #fetch-the-descendants-of-a-module-script
- [FDaI] #fetch-the-descendants-of-and-instantiate-a-module-script
- #hostresolveimportedmodule(referencingscriptormodule,-specifier)

And thus this CL updates the following accordingly:
- ModuleScript::Create()
- ModulatorImplBase::ExecuteModule()
- ModuleTreeLinker.cpp
- ScriptModuleResolverImpl::Resolve()

The behavior changes are:
- User-facing: the error reported (to window.onerror etc.) is changed
  and made deterministic, as intended by the spec update.
- V8-facing: this CL
  - invokes module instantiation of a module graph
    with existing instantiation/evaluation errors.
  - invokes evaluation of a module graph with existing evaluation errors.
  These cases already occur, but this CL does these intentionally.

Bug: 763597
Change-Id: Ia02bb484290c5c07ab27e9c966db19a6e8d2596f
Reviewed-on: https://chromium-review.googlesource.com/698467
Commit-Queue: Hiroshige Hayashizaki <[email protected]>
Reviewed-by: Kouhei Ueno <[email protected]>
Cr-Commit-Position: refs/heads/master@{#525168}
Assets 2
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