Fix LoadDataWithBaseUrlTest#testloadDataWithBaseUrlCallsOnPageStarted with PlzNavigate.

content/browser/frame_host/navigator_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/frame_host/navigator_impl.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 1157 matching lines @@
 
   frame_tree_node->CreatedNavigationRequest(std::move(scoped_request));
 
   frame_tree_node->navigation_request()->CreateNavigationHandle(
       entry.GetUniqueID());
 
   NavigationRequest* navigation_request = frame_tree_node->navigation_request();
   if (!navigation_request)
     return;  // Navigation was synchronously stopped.
 
+  navigation_request->navigation_handle()->set_base_url_for_data_url(
+      entry.GetBaseURLForDataURL());
+
   // Have the current renderer execute its beforeunload event if needed. If it
   // is not needed then NavigationRequest::BeginNavigation should be directly
   // called instead.
   if (should_dispatch_beforeunload && !IsRendererDebugURL(dest_url)) {
     navigation_request->SetWaitingForRendererResponse();
     frame_tree_node->current_frame_host()->DispatchBeforeUnload(
         true, reload_type != ReloadType::NONE);
   } else {
     navigation_request->BeginNavigation();
   }
@@ skipping 100 matching lines @@
     if (navigation_handle)
       navigation_handle->update_entry_id_for_transfer(entry->GetUniqueID());
 
     controller_->SetPendingEntry(std::move(entry));
     if (delegate_)
       delegate_->NotifyChangedNavigationState(content::INVALIDATE_TYPE_URL);
   }
 }
 
 }  // namespace content