RPP: Launch portable trace popup immediately without query params

The popup launch was delayed for unknown reasons [0] and removing this
delay appears to improve likelihood that the postMessage communication
is successful.

[0]: https://crrev.com/c/5837910/comment/637fd530_8b55ad4e/

Bug: 444526423
Change-Id: I7dd422e5e97e39d7ae32ae131fba0c77801d746f
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6940957
Commit-Queue: Connor Clark <cjamcl@chromium.org>
Auto-Submit: Paul Irish <paulirish@chromium.org>
Reviewed-by: Connor Clark <cjamcl@chromium.org>

Author: paulirish

front_end/core/sdk/RehydratingConnection.ts

@@ -83,6 +83,7 @@ export class RehydratingConnection implements ProtocolClient.InspectorBackend.Co
     this.#rehydratingWindow.addEventListener('message', this.#onReceiveHostWindowPayloadBound);
     if (!this.#rehydratingWindow.opener) {
       this.#onConnectionLost(i18nString(UIStrings.noHostWindow));
+      return;
     }
     this.#rehydratingWindow.opener.postMessage({type: 'REHYDRATING_WINDOW_READY'});
   }

front_end/panels/timeline/TimelinePanel.ts

@@ -1608,9 +1608,7 @@ export class TimelinePanel extends Common.ObjectWrapper.eventMixin<EventTypes, t
 
     const content = await Common.Gzip.fileToString(file);
     if (content.includes('enhancedTraceVersion')) {
-      await window.scheduler.postTask(() => {
-        this.#launchRehydratedSession(content);
-      }, {priority: 'background'});
+      this.#launchRehydratedSession(content);
     } else {
       this.loader = TimelineLoader.loadFromParsedJsonFile(JSON.parse(content), this);
       this.prepareToLoadTimeline();
@@ -1624,6 +1622,8 @@ export class TimelinePanel extends Common.ObjectWrapper.eventMixin<EventTypes, t
     const url = new URL(window.location.href);
     const pathToEntrypoint = url.pathname.slice(0, url.pathname.lastIndexOf('/'));
     url.pathname = `${pathToEntrypoint}/rehydrated_devtools_app.html`;
+    // The standalone devtools shouldn't retain any existing query params.
+    url.search = '';
     pathToLaunch = url.toString();
 
     // Clarifying the window the code is referring to