Use FrameIsAd to decide whether to isolate a frame in TopDocumentIsolation mode.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index af7ba906a7c3f8bf037204bf2b2fd1ef813b9836..c8b4275d5537de424b021c6173c1df17442e49bf 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -987,9 +987,9 @@ void RenderFrameHostManager::RenderProcessGone(SiteInstanceImpl* instance) {
 
 void RenderFrameHostManager::CancelPendingIfNecessary(
     RenderFrameHostImpl* render_frame_host) {
-  if (render_frame_host == pending_render_frame_host_.get())
+  if (render_frame_host == pending_render_frame_host_.get()) {
     CancelPending();
-  else if (render_frame_host == speculative_render_frame_host_.get()) {
+  } else if (render_frame_host == speculative_render_frame_host_.get()) {
     // TODO(nasko, clamy): This should just clean up the speculative RFH
     // without canceling the request.  See https://crbug.com/636119.
     if (frame_tree_node_->navigation_request() &&
@@ -1434,18 +1434,20 @@ RenderFrameHostManager::DetermineSiteInstanceForURL(
       SiteIsolationPolicy::IsTopDocumentIsolationEnabled() &&
       !SiteInstanceImpl::DoesSiteRequireDedicatedProcess(browser_context,
                                                          dest_url)) {
+    RenderFrameHostImpl* main_frame =
+        frame_tree_node_->frame_tree()->root()->current_frame_host();
     if (GetContentClient()
             ->browser()
-            ->ShouldFrameShareParentSiteInstanceDespiteTopDocumentIsolation(
-                dest_url, current_instance)) {
-      return SiteInstanceDescriptor(render_frame_host_->GetSiteInstance());
+            ->ShouldIsolateFrameForTopDocumentIsolation(
+                transfer_navigation_handle_.get(),
+                main_frame->GetSiteInstance())) {
+      // This is a cross-site subframe of a non-isolated origin, so place this
+      // frame in the default subframe site instance.
+      return SiteInstanceDescriptor(
+          browser_context, dest_url,
+          SiteInstanceRelation::RELATED_DEFAULT_SUBFRAME);
     }
-
-    // This is a cross-site subframe of a non-isolated origin, so place this
-    // frame in the default subframe site instance.
-    return SiteInstanceDescriptor(
-        browser_context, dest_url,
-        SiteInstanceRelation::RELATED_DEFAULT_SUBFRAME);
+    return SiteInstanceDescriptor(render_frame_host_->GetSiteInstance());
   }
 
   // Keep subframes in the parent's SiteInstance unless a dedicated process is