Revert of Showing previews UI for Offline Previews

chrome/browser/previews/previews_infobar_tab_helper.h

Index: chrome/browser/previews/previews_infobar_tab_helper.h
diff --git a/chrome/browser/previews/previews_infobar_tab_helper.h b/chrome/browser/previews/previews_infobar_tab_helper.h
index 3e6769bf19438073a00c4dc03cd36281784902fa..b94a42a2bba97b5fdcdde7d12e78a4487fbbff07 100644
--- a/chrome/browser/previews/previews_infobar_tab_helper.h
+++ b/chrome/browser/previews/previews_infobar_tab_helper.h
@@ -35,11 +35,6 @@
     displayed_preview_infobar_ = displayed;
   }
 
-  // Whether an offline preview has been shown for this page.
-  bool is_showing_offline_preview() const {
-    return is_showing_offline_preview_;
-  }
-
  private:
   friend class content::WebContentsUserData<PreviewsInfoBarTabHelper>;
   friend class PreviewsInfoBarTabHelperUnitTest;
@@ -47,15 +42,17 @@
   explicit PreviewsInfoBarTabHelper(content::WebContents* web_contents);
 
   // Overridden from content::WebContentsObserver:
+  void DidStartProvisionalLoadForFrame(
+      content::RenderFrameHost* render_frame_host,
+      const GURL& validated_url,
+      bool is_error_page,
+      bool is_iframe_srcdoc) override;
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;
 
   // True if the InfoBar for a preview has been shown for the page.
   bool displayed_preview_infobar_;
 
-  // Whether an offline preview has been shown for this page.
-  bool is_showing_offline_preview_;
-
   DISALLOW_COPY_AND_ASSIGN(PreviewsInfoBarTabHelper);
 };