Refactors offline page tab helper to stash the offline page item on redirect.

chrome/browser/android/offline_pages/offline_page_utils.cc

Index: chrome/browser/android/offline_pages/offline_page_utils.cc
diff --git a/chrome/browser/android/offline_pages/offline_page_utils.cc b/chrome/browser/android/offline_pages/offline_page_utils.cc
index 25d49cb9ea128b373f25b2b7136fabddd158a178..9145296dbde4ed87840c6e0ae68356490597e34f 100644
--- a/chrome/browser/android/offline_pages/offline_page_utils.cc
+++ b/chrome/browser/android/offline_pages/offline_page_utils.cc
@@ -16,11 +16,14 @@
 #include "components/offline_pages/offline_page_item.h"
 #include "components/offline_pages/offline_page_model.h"
 #include "content/public/browser/browser_context.h"
+#include "content/public/browser/web_contents.h"
 #include "url/gurl.h"
 
 namespace offline_pages {
 namespace {
 
+const char kWebContentsUserDataKey[] = "OfflinePageForTab";
+
 // Returns an offline page originated from the |online_url|.
 const OfflinePageItem* MaybeGetBestOfflinePageForOnlineURL(
     content::BrowserContext* browser_context,
@@ -179,4 +182,23 @@ void OfflinePageUtils::MarkPageAccessed(
   offline_page_model->MarkPageAccessed(offline_page->offline_id);
 }
 
+const OfflinePageItem* OfflinePageUtils::GetCurrentOfflinePage(
+    content::WebContents* web_contents) {
+  return static_cast<const OfflinePageItem*>(
+      web_contents->GetUserData(kWebContentsUserDataKey));
+}
+
+void OfflinePageUtils::SetCurrentOfflinePage(
+    content::WebContents* web_contents,
+    const OfflinePageItem* offline_page) {
+  if (!offline_page) {
+    web_contents->RemoveUserData(kWebContentsUserDataKey);
+    return;
+  }
+
+  // |SetUserData| takes ownership of the data object, so we need to make a copy
+  // here.
+  web_contents->SetUserData(kWebContentsUserDataKey,
+                            new OfflinePageItem(*offline_page));
+}
 }  // namespace offline_pages