Enable module scripts in ScriptLoader

third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp

Index: third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp
diff --git a/third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp b/third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp
index 9c66b2d3af5288cdaa5eb1c8e649ac3c2bf90563..2cad737cb5412d8e053bde6c3dda22a82eff006d 100644
--- a/third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp
+++ b/third_party/WebKit/Source/core/xml/parser/XMLDocumentParser.cpp
@@ -1112,9 +1112,14 @@ void XMLDocumentParser::EndElementNs() {
   DCHECK(!pending_script_);
   requesting_script_ = true;
 
-  if (script_loader->PrepareScript(
-          script_start_position_,
-          ScriptLoader::kAllowLegacyTypeInTypeAttribute)) {
+  bool success = script_loader->PrepareScript(
+      script_start_position_, ScriptLoader::kAllowLegacyTypeInTypeAttribute);
+
+  // XMLDocumentParser does not support module scripts.
+  // FOXME: (how) should we handle this? Should we fail more gracefully?
+  CHECK_EQ(script_loader->GetScriptType(), ScriptType::kClassic);

[kouhei (in TOK), 2017/04/24 01:24:04]

If PrepareScript is ensured to fail in XML document, we should
CHECK_EQ->DCHECK_EQ(after unflag)

If PrepareScript may succeed in XML documents, we should "success = false" and
report it via VLOG

[hiroshige, 2017/04/26 01:09:34]

(Probably) no because ScriptLoader doesn't check whether it is called from
XMLDocument.
Done.

[kouhei (in TOK), 2017/04/26 02:05:27]

Sorry for the back-and-forth （≧∞≦）
Now I think PrepareScript *does* need to care if its in XML doc or not in
itself, as that may kick module tree fetch.

[hiroshige, 2017/04/26 19:10:21]

Hmm. To do so, I think PrepareScript() should take an additional parameter that
indicates whether module script should be invoked or not.

However, I'm not so sure how important that we should block fetching in this
case.
If <script module> is created by JavaScript inside an XML document, then it is
fetched and executed (because it is not processed by this code path IIUC).
I want to disable *parser-inserted* <script module> in an XML document because
we need more implementation for that.

+
+  if (success) {
     // FIXME: Script execution should be shared between
     // the libxml2 and Qt XMLDocumentParser implementations.