Allow SharedStorage APIs in FLEDGE fenced frames.

Right now, features like SharedStorage's selectURL() are not allowed
inside of a fenced frame created with FLEDGE. There is no
security/privacy benefit to having this restriction, so it should be
removed to have consistent behavior across fenced frames loaded with
different APIs.

Bug: 1450902
Change-Id: I5714e584ee445eab2d2c42c654cb0fd1971ce691
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4584988
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Josh Karlin <jkarlin@chromium.org>
Commit-Queue: Liam Brady <lbrady@google.com>
Cr-Commit-Position: refs/heads/main@{#1152619}

third_party/blink/common/permissions_policy/permissions_policy_unittest.cc

@@ -2606,7 +2606,7 @@ TEST_F(PermissionsPolicyTest, CreateForFledgeFencedFrame) {
   EXPECT_FALSE(policy->IsFeatureEnabled(kDefaultSelfFeature));
   EXPECT_TRUE(policy->IsFeatureEnabled(
       mojom::PermissionsPolicyFeature::kAttributionReporting));
-  EXPECT_FALSE(policy->IsFeatureEnabled(
+  EXPECT_TRUE(policy->IsFeatureEnabled(
       mojom::PermissionsPolicyFeature::kSharedStorage));
 }
 

third_party/blink/public/common/frame/fenced_frame_permissions_policies.h

@@ -15,7 +15,9 @@ namespace blink {
 constexpr blink::mojom::PermissionsPolicyFeature
     kFencedFrameFledgeDefaultRequiredFeatures[] = {
         blink::mojom::PermissionsPolicyFeature::kAttributionReporting,
-        blink::mojom::PermissionsPolicyFeature::kPrivateAggregation};
+        blink::mojom::PermissionsPolicyFeature::kPrivateAggregation,
+        blink::mojom::PermissionsPolicyFeature::kSharedStorage,
+        blink::mojom::PermissionsPolicyFeature::kSharedStorageSelectUrl};
 
 constexpr blink::mojom::PermissionsPolicyFeature
     kFencedFrameSharedStorageDefaultRequiredFeatures[] = {

third_party/blink/web_tests/external/wpt/fenced-frame/resources/default-enabled-features-helper.js

@@ -31,15 +31,23 @@ async function runDefaultEnabledFeaturesTest(t, should_load, fenced_origin,
         "frame loaded using FLEDGE or shared storage.");
 
     if (generator_api == "fledge") {
-      assert_false(
+      assert_true(
             document.featurePolicy.allowsFeature('shared-storage'),
-            "Shared storage should be disallowed if the fenced " +
+            "Shared Storage should be allowed if the fenced " +
+            "frame loaded using FLEDGE.");
+      assert_true(
+            document.featurePolicy.allowsFeature('private-aggregation'),
+            "Private Aggregation should be allowed if the fenced " +
             "frame loaded using FLEDGE.");
     } else {
       assert_true(
             document.featurePolicy.allowsFeature('shared-storage'),
-            "Shared storage should be allowed if the fenced " +
-            "frame loaded using shared storage.");
+            "Shared Storage should be allowed if the fenced " +
+            "frame loaded using Shared Storage.");
+      assert_false(
+            document.featurePolicy.allowsFeature('private-aggregation'),
+            "Private Aggregation should be disabled if the fenced " +
+            "frame loaded using Shared Storage.");
     }
   }, [generator_api]);
 }