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

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 6461d76826efa245ffa8394dd215028ea1f5938e..d7221ad034a948d4f8667087c231bc284d236d51 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -19,6 +19,7 @@
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/field_trial_params.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/strings/string_number_conversions.h"
@@ -57,6 +58,7 @@
 #include "chrome/browser/notifications/platform_notification_service_impl.h"
 #include "chrome/browser/page_load_metrics/experiments/delay_navigation_throttle.h"
 #include "chrome/browser/page_load_metrics/metrics_navigation_throttle.h"
+#include "chrome/browser/page_load_metrics/observers/ads_detection.h"
 #include "chrome/browser/password_manager/chrome_password_manager_client.h"
 #include "chrome/browser/permissions/permission_context_base.h"
 #include "chrome/browser/platform_util.h"
@@ -1338,20 +1340,36 @@ void ChromeContentBrowserClient::OverrideNavigationParams(
 #endif
 }
 
-bool ChromeContentBrowserClient::
-    ShouldFrameShareParentSiteInstanceDespiteTopDocumentIsolation(
-        const GURL& url,
-        content::SiteInstance* parent_site_instance) {
-  if (IsNTPSiteInstance(parent_site_instance))
-    return true;
+bool ChromeContentBrowserClient::ShouldIsolateFrameFromMainContent(
+    content::RenderFrameHost* frame,
+    const GURL& dest_url,
+    content::SiteInstance* main_frame_site_instance) {
+  if (IsNTPSiteInstance(main_frame_site_instance))
+    return false;
 
 #if BUILDFLAG(ENABLE_EXTENSIONS)
-  return ChromeContentBrowserClientExtensionsPart::
-      ShouldFrameShareParentSiteInstanceDespiteTopDocumentIsolation(
-          url, parent_site_instance);
-#else
-  return false;
+  if (ChromeContentBrowserClientExtensionsPart::
+          IsMainFrameSiteInstanceExcludedFromTopDocumentIsolation(
+              main_frame_site_instance))
+    return false;
 #endif
+
+  features::TopDocumentIsolationMode tdiMode =
+      static_cast<features::TopDocumentIsolationMode>(
+          base::GetFieldTrialParamByFeatureAsInt(
+              ::features::kTopDocumentIsolation,
+              ::features::kTopDocumentIsolationModeParam,
+              static_cast<int>(features::TopDocumentIsolationMode::Default)));
+  switch (tdiMode) {
+    case features::TopDocumentIsolationMode::Default:
+    case features::TopDocumentIsolationMode::Ads:
+      return IsAdFrame(frame->GetFrameName(), dest_url);
+
+    case features::TopDocumentIsolationMode::Xsite:
+      return true;
+  }
+  NOTREACHED();
+  return false;
 }
 
 bool ChromeContentBrowserClient::IsSuitableHost(