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

chrome/browser/android/tab_android.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/tab_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/metrics/histogram.h"
@@ skipping 283 matching lines @@
       offline_pages::OfflinePageModelFactory::GetForBrowserContext(
           GetProfile());
   return !offline_page_model->GetAllPages().empty();
 }
 
 void TabAndroid::ShowOfflinePages() {
   JNIEnv* env = base::android::AttachCurrentThread();
   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,
                                  bool did_finish_load) {
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_Tab_swapWebContents(
       env,
       weak_java_tab_.get(env).obj(),
       new_contents->GetJavaWebContents().obj(),
       did_start_load,
@@ skipping 448 matching lines @@
 void TabAndroid::LoadOriginalImage(JNIEnv* env, jobject obj) {
   content::RenderFrameHost* render_frame_host =
       web_contents()->GetFocusedFrame();
   render_frame_host->Send(new ChromeViewMsg_RequestReloadImageForContextNode(
       render_frame_host->GetRoutingID()));
 }
 
 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();
 
   // If the url points to an offline page, replace it with the original url.
   const offline_pages::OfflinePageItem* offline_page = GetOfflinePage(url);
   if (offline_page)
     url = offline_page->url;
 
   // Get all the nodes for |url| and sort them by date added.
   std::vector<const bookmarks::BookmarkNode*> nodes;
   bookmarks::ManagedBookmarkService* managed =
       ManagedBookmarkServiceFactory::GetForProfile(profile);
   bookmarks::BookmarkModel* model =
       BookmarkModelFactory::GetForProfile(profile);
   model->GetNodesByURL(url, &nodes);
   std::sort(nodes.begin(), nodes.end(), &bookmarks::MoreRecentlyAdded);
 
   // Return the first node matching the search criteria.
   for (size_t i = 0; i < nodes.size(); ++i) {
     if (only_editable && !managed->CanBeEditedByUser(nodes[i]))
       continue;
     return nodes[i]->id();
   }
 
   return -1;
 }
 
 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;
 
   offline_pages::OfflinePageModel* offline_page_model =
       offline_pages::OfflinePageModelFactory::GetForBrowserContext(
           GetProfile());
   if (!offline_page_model)
     return false;
   const offline_pages::OfflinePageItem* offline_page =
       offline_page_model->GetPageByBookmarkId(bookmark_id);
@@ skipping 110 matching lines @@
 static void Init(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   TRACE_EVENT0("native", "TabAndroid::Init");
   // This will automatically bind to the Java object and pass ownership there.
   new TabAndroid(env, obj);
 }
 
 // static
 bool TabAndroid::RegisterTabAndroid(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }