Fenced frames: Update Shared Storage browser tests to test

`selectURL()` that returns a FencedFrameConfig.

crrev.com/c/4111682 enables `selectURL()` to return a
FencedFrameConfig object by specifying the new boolean dictionary
member in SharedStorageRunOperationMethodOptions as true. This CL
updates the test cases in
1. shared_storage/shared_storage_browsertest.cc
2. storage/shared_storage_browsertest.cc
to test this new behavior.

A test-only observer is added to observe
1. the generated urn::uuid.
2. the populated FencedFrameConfig.

It's needed because we cannot obtained the urn::uuid from the returned
FencedFrameConfig object. It is designed to be opaque to the web platform. For example:

const fenced_frame_config = await sharedStorage.selectURL(...);
const urn = fenced_frame_config.urn; // Cannot do this

Bug: 1347953
Change-Id: Id580664ab029e4337041ca69911353c1b90c2929
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4127118
Reviewed-by: Dominic Farolino <dom@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Commit-Queue: Xiaochen Zhou <xiaochenzh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1106897}

content/browser/devtools/protocol/storage_handler.cc

@@ -294,6 +294,11 @@ class StorageHandler::SharedStorageObserver
                                         owner_origin, params);
   }
 
+  void OnUrnUuidGenerated(const GURL& urn_uuid) override {}
+
+  void OnConfigPopulated(
+      const absl::optional<FencedFrameConfig>& config) override {}
+
  private:
   raw_ptr<StorageHandler> const owner_;
   base::ScopedObservation<

content/browser/fenced_frame/fenced_frame_url_mapping.cc

@@ -219,7 +219,8 @@ void FencedFrameURLMapping::RemoveObserverForURN(
   it->second.erase(observer_it);
 }
 
-void FencedFrameURLMapping::OnSharedStorageURNMappingResultDetermined(
+absl::optional<FencedFrameConfig>
+FencedFrameURLMapping::OnSharedStorageURNMappingResultDetermined(
     const GURL& urn_uuid,
     const SharedStorageURNMappingResult& mapping_result) {
   auto pending_it = pending_urn_uuid_to_url_map_.find(urn_uuid);
@@ -254,6 +255,8 @@ void FencedFrameURLMapping::OnSharedStorageURNMappingResultDetermined(
   }
 
   pending_urn_uuid_to_url_map_.erase(pending_it);
+
+  return config;
 }
 
 SharedStorageBudgetMetadata*

content/browser/fenced_frame/fenced_frame_url_mapping.h

@@ -31,6 +31,9 @@ using SharedStorageReportingMap = base::flat_map<std::string, ::GURL>;
 // Keeps a mapping of fenced frames URN:UUID and URL. Also keeps a set of
 // pending mapped URN:UUIDs to support asynchronous mapping. See
 // https://github.com/WICG/fenced-frame/blob/master/explainer/opaque_src.md
+// TODO(crbug.com/1405477): Add methods for:
+// 1. generating the pending config.
+// 2. finalizing the pending config.
 class CONTENT_EXPORT FencedFrameURLMapping {
  public:
   // The runURLSelectionOperation's url mapping result. It contains the mapped
@@ -126,7 +129,12 @@ class CONTENT_EXPORT FencedFrameURLMapping {
   // will trigger the observers' OnFencedFrameURLMappingComplete() method
   // associated with the `urn_uuid`, unregister those observers, and move the
   // `urn_uuid` from `pending_urn_uuid_to_url_map_` to `urn_uuid_to_url_map_`.
-  void OnSharedStorageURNMappingResultDetermined(
+  // If the resolved URL is fenced-frame-compatible, the return value is the
+  // populated fenced frame config. It is used to notify the observers in shared
+  // storage worklet host manager. Tests can then obtain the populated fenced
+  // frame configs from the observers.
+  // Otherwise this method returns an absl::nullopt.
+  absl::optional<FencedFrameConfig> OnSharedStorageURNMappingResultDetermined(
       const GURL& urn_uuid,
       const SharedStorageURNMappingResult& mapping_result);