diff --git a/src/webkit/wkPage.ts b/src/webkit/wkPage.ts
index a6af66fa19..36e53d71e5 100644
--- a/src/webkit/wkPage.ts
+++ b/src/webkit/wkPage.ts
@@ -60,7 +60,7 @@ export class WKPage implements PageDelegate {
     this._session = undefined as any as WKSession;
   }
 
-  async _initializePageProxySession() {
+  private async _initializePageProxySession() {
     const promises : Promise<any>[] = [
       this._pageProxySession.send('Dialog.enable'),
       this._networkManager.initializePageProxySession(this._page._state.credentials)
@@ -87,25 +87,29 @@ export class WKPage implements PageDelegate {
       this._setBootstrapScripts(session).catch(e => debugError(e));
   }
 
+  async initialize() {
+    await Promise.all([
+      this._initializePageProxySession(),
+      this._initializeSession(this._session, ({frameTree}) => this._handleFrameTree(frameTree)),
+    ]);
+  }
+
   // This method is called for provisional targets as well. The session passed as the parameter
   // may be different from the current session and may be destroyed without becoming current.
-  async _initializeSession(session: WKSession) {
+  async _initializeSession(session: WKSession, resourceTreeHandler: (r: Protocol.Page.getResourceTreeReturnValue) => void) {
     const isProvisional = this._session !== session;
     const promises : Promise<any>[] = [
       // Page agent must be enabled before Runtime.
-      session.send('Page.enable')
+      session.send('Page.enable'),
+      session.send('Page.getResourceTree').then(resourceTreeHandler),
+      // Resource tree should be received before first execution context.
+      session.send('Runtime.enable'),
+      session.send('Page.createIsolatedWorld', { name: UTILITY_WORLD_NAME, source: `//# sourceURL=${EVALUATION_SCRIPT_URL}` }),
+      session.send('Console.enable'),
+      session.send('Page.setInterceptFileChooserDialog', { enabled: true }),
+      this._networkManager.initializeSession(session, this._page._state.interceptNetwork, this._page._state.offlineMode),
+      this._workers.initializeSession(session)
     ];
-    if (!isProvisional)
-      promises.push(session.send('Page.getResourceTree').then(({frameTree}) => this._handleFrameTree(frameTree)));
-    promises.push(
-        // Resource tree should be received before first execution context.
-        session.send('Runtime.enable'),
-        session.send('Page.createIsolatedWorld', { name: UTILITY_WORLD_NAME, source: `//# sourceURL=${EVALUATION_SCRIPT_URL}` }),
-        session.send('Console.enable'),
-        session.send('Page.setInterceptFileChooserDialog', { enabled: true }),
-        this._networkManager.initializeSession(session, this._page._state.interceptNetwork, this._page._state.offlineMode),
-        this._workers.initializeSession(session)
-    );
     const contextOptions = this._page.browserContext()._options;
     if (contextOptions.userAgent)
       promises.push(session.send('Page.overrideUserAgent', { value: contextOptions.userAgent }));
@@ -190,10 +194,7 @@ export class WKPage implements PageDelegate {
   }
 
   _onFrameNavigated(framePayload: Protocol.Page.Frame, initial: boolean) {
-    let frame = this._page._frameManager.frame(framePayload.id);
-    const newProcessMainFrame = !frame && !framePayload.parentId;
-    if (newProcessMainFrame)
-      frame = this._page._frameManager.mainFrame();
+    const frame = this._page._frameManager.frame(framePayload.id);
     for (const [contextId, context] of this._contextIdToContext) {
       if (context.frame === frame) {
         (context._delegate as WKExecutionContext)._dispose();
@@ -201,8 +202,6 @@ export class WKPage implements PageDelegate {
         frame._contextDestroyed(context);
       }
     }
-    if (newProcessMainFrame)
-      this._onFrameAttached(framePayload.id, null);
     this._page._frameManager.frameCommittedNewDocumentNavigation(framePayload.id, framePayload.url, framePayload.name || '', framePayload.loaderId, initial);
   }
 
diff --git a/src/webkit/wkPageProxy.ts b/src/webkit/wkPageProxy.ts
index f30a226b7e..a516145f32 100644
--- a/src/webkit/wkPageProxy.ts
+++ b/src/webkit/wkPageProxy.ts
@@ -124,10 +124,7 @@ export class WKPageProxy {
     assert(session, 'One non-provisional target session must exist');
     this._wkPage = new WKPage(this._browserContext, this._pageProxySession);
     this._wkPage.setSession(session!);
-    await Promise.all([
-      this._wkPage._initializePageProxySession(),
-      this._wkPage._initializeSession(session!),
-    ]);
+    await this._wkPage.initialize();
     return this._wkPage._page;
   }
 
@@ -151,7 +148,6 @@ export class WKPageProxy {
     if (targetInfo.isProvisional && this._wkPage) {
       assert(!this._provisionalPage);
       this._provisionalPage = new WKProvisionalPage(session, this._wkPage);
-      this._wkPage._initializeSession(session);
     }
     if (targetInfo.isPaused)
       this._pageProxySession.send('Target.resume', { targetId: targetInfo.targetId }).catch(debugError);
@@ -188,6 +184,7 @@ export class WKPageProxy {
     oldSession!.errorText = 'Target was swapped out.';
     (newSession as any)[isPovisionalSymbol] = undefined;
     if (this._provisionalPage) {
+      this._provisionalPage.commit();
       this._provisionalPage.dispose();
       this._provisionalPage = null;
     }
diff --git a/src/webkit/wkProvisionalPage.ts b/src/webkit/wkProvisionalPage.ts
index 318216f293..6e89018e62 100644
--- a/src/webkit/wkProvisionalPage.ts
+++ b/src/webkit/wkProvisionalPage.ts
@@ -16,12 +16,14 @@
 
 import { WKSession } from './wkConnection';
 import { WKPage } from './wkPage';
-import { RegisteredListener, helper } from '../helper';
+import { RegisteredListener, helper, assert } from '../helper';
+import { Protocol } from './protocol';
 
 export class WKProvisionalPage {
   readonly _session: WKSession;
   private readonly _wkPage: WKPage;
   private _sessionListeners: RegisteredListener[] = [];
+  private _mainFrameId: string | null = null;
 
   constructor(session: WKSession, page: WKPage) {
     this._session = session;
@@ -34,7 +36,19 @@ export class WKProvisionalPage {
       'Network.loadingFinished',
       'Network.loadingFailed',
     ].map(name => helper.addEventListener(this._session, name, args => this._onNetworkEvent(name, args)));
+
+    this._wkPage._initializeSession(session, ({frameTree}) => this._handleFrameTree(frameTree));
   }
+
+  dispose() {
+    helper.removeEventListeners(this._sessionListeners);
+  }
+
+  commit() {
+    assert(this._mainFrameId);
+    this._wkPage._onFrameAttached(this._mainFrameId!, null);
+  }
+
   private _onNetworkEvent(eventName: string, payload: any) {
     // Pretend that the events happened in the same process.
     if (payload.frameId)
@@ -42,7 +56,8 @@ export class WKProvisionalPage {
     this._wkPage._session.emit(eventName, payload);
   }
 
-  dispose() {
-    helper.removeEventListeners(this._sessionListeners);
+  private _handleFrameTree(frameTree: Protocol.Page.FrameResourceTree) {
+    assert(!frameTree.frame.parentId);
+    this._mainFrameId = frameTree.frame.id;
   }
 }
\ No newline at end of file