Worker: Move implementation of the "fetch a module worker script graph" algorithm

This CL moves implementation of the "fetch a module worker script graph"
algorithm from WorkletGlobalScope to WorkerOrWorkletGlobalScope so that it can
be reused for module workers.

There is no behavioral change.

Bug: 680046
Change-Id: I7eba8ec1e1dc65396ec2aea8486b22fd1d829fa2
Reviewed-on: https://chromium-review.googlesource.com/826206Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524641}

third_party/WebKit/Source/core/workers/WorkerOrWorkletGlobalScope.cpp

@@ -10,6 +10,7 @@
 #include "core/frame/Deprecation.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/loader/WorkerFetchContext.h"
+#include "core/loader/modulescript/ModuleScriptFetchRequest.h"
 #include "core/probe/CoreProbes.h"
 #include "core/workers/MainThreadWorkletGlobalScope.h"
 #include "core/workers/WorkerReportingProxy.h"
@@ -195,6 +196,28 @@ void WorkerOrWorkletGlobalScope::ApplyContentSecurityPolicyFromVector(
   GetContentSecurityPolicy()->BindToExecutionContext(GetExecutionContext());
 }
 
+void WorkerOrWorkletGlobalScope::FetchModuleScript(
+    const KURL& module_url_record,
+    network::mojom::FetchCredentialsMode credentials_mode,
+    ModuleTreeClient* client) {
+  // Step 2: "Let options be a script fetch options whose cryptographic nonce is
+  // the empty string,
+  String nonce;
+  // integrity metadata is the empty string,
+  String integrity_attribute;
+  // parser metadata is "not-parser-inserted",
+  ParserDisposition parser_state = kNotParserInserted;
+  // and credentials mode is credentials mode."
+  ScriptFetchOptions options(nonce, IntegrityMetadataSet(), integrity_attribute,
+                             parser_state, credentials_mode);
+
+  Modulator* modulator = Modulator::From(ScriptController()->GetScriptState());
+  // Step 3. "Perform the internal module script graph fetching procedure ..."
+  ModuleScriptFetchRequest module_request(
+      module_url_record, modulator->GetReferrerPolicy(), options);
+  modulator->FetchTree(module_request, client);
+}
+
 void WorkerOrWorkletGlobalScope::Trace(blink::Visitor* visitor) {
   visitor->Trace(resource_fetcher_);
   visitor->Trace(script_controller_);

third_party/WebKit/Source/core/workers/WorkerOrWorkletGlobalScope.h

@@ -14,10 +14,12 @@
 #include "core/workers/WorkerClients.h"
 #include "core/workers/WorkerEventQueue.h"
 #include "platform/wtf/BitVector.h"
+#include "services/network/public/interfaces/fetch_api.mojom-shared.h"
 
 namespace blink {
 
 class Modulator;
+class ModuleTreeClient;
 class ResourceFetcher;
 class V8AbstractEventListener;
 class WorkerOrWorkletScriptController;
@@ -112,6 +114,13 @@ class CORE_EXPORT WorkerOrWorkletGlobalScope : public EventTargetWithInlineData,
   void ApplyContentSecurityPolicyFromVector(
       const Vector<CSPHeaderAndType>& headers);
 
+  // Implementation of the "fetch a module worker script graph" algorithm in the
+  // HTML spec:
+  // https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-module-worker-script-tree
+  void FetchModuleScript(const KURL& module_url_record,
+                         network::mojom::FetchCredentialsMode,
+                         ModuleTreeClient*);
+
  private:
   CrossThreadPersistent<WorkerClients> worker_clients_;
   Member<ResourceFetcher> resource_fetcher_;

third_party/WebKit/Source/core/workers/WorkletGlobalScope.cpp

@@ -10,7 +10,6 @@
 #include "bindings/core/v8/WorkerOrWorkletScriptController.h"
 #include "core/dom/Modulator.h"
 #include "core/inspector/MainThreadDebugger.h"
-#include "core/loader/modulescript/ModuleScriptFetchRequest.h"
 #include "core/probe/CoreProbes.h"
 #include "core/workers/GlobalScopeCreationParams.h"
 #include "core/workers/WorkerReportingProxy.h"
@@ -100,30 +99,14 @@ void WorkletGlobalScope::FetchAndInvokeScript(
   // moduleURLRecord, moduleResponsesMap, credentialOptions, outsideSettings,
   // and insideSettings when it asynchronously completes."
 
-  // [FMWST]
-  // https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-module-worker-script-tree
-  // [FMWST] Step 2: "Let options be a script fetch options whose cryptographic
-  // nonce is the empty string,
-  String nonce;
-  // integrity metadata is the empty string,
-  String integrity_attribute;
-  // parser metadata is "not-parser-inserted",
-  ParserDisposition parser_state = kNotParserInserted;
-  // and credentials mode is credentials mode.
-  ScriptFetchOptions options(nonce, IntegrityMetadataSet(), integrity_attribute,
-                             parser_state, credentials_mode);
-
   Modulator* modulator = Modulator::From(ScriptController()->GetScriptState());
-  // [FMWST] Step 3. "Perform the internal module script graph fetching
-  // procedure ..."
-  ModuleScriptFetchRequest module_request(
-      module_url_record, modulator->GetReferrerPolicy(), options);
 
   // Step 3 to 5 are implemented in
   // WorkletModuleTreeClient::NotifyModuleTreeLoadFinished.
   WorkletModuleTreeClient* client = new WorkletModuleTreeClient(
       modulator, std::move(outside_settings_task_runner), pending_tasks);
-  modulator->FetchTree(module_request, client);
+
+  FetchModuleScript(module_url_record, credentials_mode, client);
 }
 
 WorkletModuleResponsesMapProxy* WorkletGlobalScope::ModuleResponsesMapProxy()