[shared storage] Record usage for when addModule() is called with cro…

…ss-origin script

Why: We proposed a potentially breaking change to addModule() in
WICG/shared-storage#158. That is, currently,
a website can call addModule() everywhere and expect it to fail when
they're not in their own context; however, with cross-origin script
support, these calls could unexpectedly succeed.

Thus, we track potentially non-forward-compatible addModule() usages to
assess the potential impact and guide further decisions. We anticipate
this usage to be low.

Bug: 350764023
Change-Id: I5da4583ed583baa398bdb2cadf8955d341474050
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5665746
Reviewed-by: Josh Karlin <jkarlin@chromium.org>
Commit-Queue: Yao Xiao <yaoxia@chromium.org>
Reviewed-by: Sun Yueru <yrsun@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1322541}

components/page_load_metrics/browser/observers/use_counter/ukm_features.cc

@@ -400,6 +400,7 @@ UseCounterMetricsRecorder::GetAllowedUkmFeatures() {
           WebFeature::kV8GPUAdapter_RequestAdapterInfo_Method,
           WebFeature::
               kSharedStorageAPI_CreateWorklet_CrossOriginScriptDefaultDataOrigin,
+          WebFeature::kSharedStorageAPI_AddModule_CrossOriginScript,
       }));
   return *opt_in_features;
 }

third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom

@@ -4394,6 +4394,7 @@ enum WebFeature {
   kV8MLContext_Dispatch_Method = 5025,
   kCSSMixins = 5026,
   kDurationFormat = 5027,
+  kSharedStorageAPI_AddModule_CrossOriginScript = 5028,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots. Also don't add extra

third_party/blink/renderer/modules/shared_storage/shared_storage_worklet.cc

@@ -145,6 +145,16 @@ void SharedStorageWorklet::AddModuleHelper(
   scoped_refptr<SecurityOrigin> script_security_origin =
       SecurityOrigin::Create(script_source_url);
 
+  if (!resolve_to_worklet &&
+      !execution_context->GetSecurityOrigin()->IsSameOriginWith(
+          script_security_origin.get())) {
+    // This `addModule()` call could be affected by the breaking change
+    // proposed in https://github.com/WICG/shared-storage/pull/158. Measure its
+    // usage.
+    execution_context->CountUse(
+        WebFeature::kSharedStorageAPI_AddModule_CrossOriginScript);
+  }
+
   if (!cross_origin_script_allowed_ &&
       !execution_context->GetSecurityOrigin()->IsSameOriginWith(
           script_security_origin.get())) {

tools/metrics/histograms/enums.xml

@@ -11157,6 +11157,7 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="5025" label="V8MLContext_Dispatch_Method"/>
   <int value="5026" label="CSSMixins"/>
   <int value="5027" label="DurationFormat"/>
+  <int value="5028" label="SharedStorageAPI_AddModule_CrossOriginScript"/>
 </enum>
 
 <enum name="FeaturePolicyFeature">