Only show Last N Pages in the UI when the corresponding tab is visible.

chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc

Index: chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc
diff --git a/chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc b/chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc
index d7ef68da8e7b52ea94767a452fff64b193746b81..1e4fcdd698d261925bd4a6cf9ab6666309ef516e 100644
--- a/chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc
+++ b/chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc
@@ -58,6 +58,7 @@ class DownloadUIAdapterDelegate : public DownloadUIAdapter::Delegate {
   // DownloadUIAdapter::Delegate
   bool IsVisibleInUI(const ClientId& client_id) override;
   bool IsTemporarilyHiddenInUI(const ClientId& client_id) override;
+  void SetUIAdapter(DownloadUIAdapter* ui_adapter) override;
 
  private:
   // Not owned, cached service pointer.
@@ -78,6 +79,8 @@ bool DownloadUIAdapterDelegate::IsTemporarilyHiddenInUI(
   return false;
 }
 
+void DownloadUIAdapterDelegate::SetUIAdapter(DownloadUIAdapter* ui_adapter) {}
+
 // TODO(dewittj): Move to Download UI Adapter.
 content::WebContents* GetWebContentsFromJavaTab(
     const ScopedJavaGlobalRef<jobject>& j_tab_ref) {