[extensions] Fail-open determining if extensions may see a (file) URL

We prevent language extensions from learning about file URLs unless they
already have file access. If a URL string fails to parse we should allow
it, since even if it's a relative URL we also validate the base.

Fixed: 396169337
Change-Id: I11f8a6f0c6f3b7c67c73c61dcdf9511137bbca04
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6263086
Auto-Submit: Philip Pfaffe <[email protected]>
Commit-Queue: Danil Somsikov <[email protected]>
Reviewed-by: Danil Somsikov <[email protected]>

Author: pfaffe

front_end/models/extensions/LanguageExtensionEndpoint.test.ts

@@ -58,6 +58,8 @@ for (const allowFileAccess of [true, false]) {
       assert.lengthOf(endpointProxyStub.getCalls(), allowFileAccess ? 3 : 1);
       await endpoint.addRawModule('', '', {url: 'http://example.com'});
       assert.lengthOf(endpointProxyStub.getCalls(), allowFileAccess ? 4 : 2);
+      await endpoint.addRawModule('', 'wasm.debug.wasm', {url: 'http://example.com'});
+      assert.lengthOf(endpointProxyStub.getCalls(), allowFileAccess ? 5 : 3);
     });
   });
 }

front_end/models/extensions/LanguageExtensionEndpoint.ts

@@ -57,7 +57,8 @@ export class LanguageExtensionEndpoint implements Bindings.DebuggerLanguagePlugi
     try {
       return !url || this.allowFileAccess || new URL(url).protocol !== 'file:';
     } catch {
-      return false;
+      // If the URL isn't valid, it also isn't a valid file url and it's safe to tell the extensions about it.
+      return true;
     }
   }