Add "Show saved copy" button in dino page when there's offline copy

chrome/browser/android/tab_android.cc

Index: chrome/browser/android/tab_android.cc
diff --git a/chrome/browser/android/tab_android.cc b/chrome/browser/android/tab_android.cc
index 2d0e15b561ec78ae2a5e4b15d6782c5c23994661..d8f66ed30a5a2e7d2ffc957e0e22b32501d0d879 100644
--- a/chrome/browser/android/tab_android.cc
+++ b/chrome/browser/android/tab_android.cc
@@ -301,6 +301,32 @@ void TabAndroid::ShowOfflinePages() {
   Java_Tab_showOfflinePages(env, weak_java_tab_.get(env).obj());
 }
 
+void TabAndroid::LoadOfflineCopy(const GURL& url) {
+  if (!offline_pages::IsOfflinePagesEnabled())
+    return;
+
+  // Offline copy is only saved for a bookmarked page.
+  int64_t bookmark_id = GetBookmarkIdHelper(true);
+  if (bookmark_id == -1)
+    return;
+
+  offline_pages::OfflinePageModel* offline_page_model =
+      offline_pages::OfflinePageModelFactory::GetForBrowserContext(
+          GetProfile());
+  if (!offline_page_model)
+    return;
+  const offline_pages::OfflinePageItem* offline_page =
+      offline_page_model->GetPageByBookmarkId(bookmark_id);
+  if (!offline_page)
+    return;
+  GURL offline_url = offline_page->GetOfflineURL();
+  if (!offline_url.is_valid())
+    return;
+
+  content::NavigationController::LoadURLParams load_params(offline_url);
+  web_contents()->GetController().LoadURLWithParams(load_params);
+}
+
 void TabAndroid::SwapTabContents(content::WebContents* old_contents,
                                  content::WebContents* new_contents,
                                  bool did_start_load,
@@ -769,6 +795,10 @@ void TabAndroid::LoadOriginalImage(JNIEnv* env, jobject obj) {
 jlong TabAndroid::GetBookmarkId(JNIEnv* env,
                                jobject obj,
                                jboolean only_editable) {
+  return GetBookmarkIdHelper(only_editable);
+}
+
+int64_t TabAndroid::GetBookmarkIdHelper(bool only_editable) const {
   GURL url = dom_distiller::url_utils::GetOriginalUrlFromDistillerUrl(
       web_contents()->GetURL());
   Profile* profile = GetProfile();
@@ -798,8 +828,12 @@ jlong TabAndroid::GetBookmarkId(JNIEnv* env,
 }
 
 jboolean TabAndroid::HasOfflineCopy(JNIEnv* env, jobject obj) {
+  return HasOfflineCopyForCurrentPage();
+}
+
+bool TabAndroid::HasOfflineCopyForCurrentPage() const {
   // Offline copy is only saved for a bookmarked page.
-  jlong bookmark_id = GetBookmarkId(env, obj, true);
+  int64_t bookmark_id = GetBookmarkIdHelper(true);
   if (bookmark_id == -1)
     return false;