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

chrome/browser/net/net_error_tab_helper.cc

Index: chrome/browser/net/net_error_tab_helper.cc
diff --git a/chrome/browser/net/net_error_tab_helper.cc b/chrome/browser/net/net_error_tab_helper.cc
index a0e73cf6cb1e2c50084dc6ce1a1817860884b2fe..fa1b47f8fedc58286cb5a5675cf7b5c57f41b94f 100644
--- a/chrome/browser/net/net_error_tab_helper.cc
+++ b/chrome/browser/net/net_error_tab_helper.cc
@@ -13,18 +13,25 @@
 #include "chrome/browser/net/net_error_diagnostics_dialog.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/localized_error.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/render_messages.h"
 #include "components/error_page/common/net_error_info.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_entry.h"
+#include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "ipc/ipc_message_macros.h"
 #include "net/base/net_errors.h"
 #include "url/gurl.h"
 
 #if defined(OS_ANDROID)
+#include "chrome/browser/android/offline_pages/offline_page_model_factory.h"
 #include "chrome/browser/android/tab_android.h"
-#endif
+#include "components/offline_pages/offline_page_feature.h"
+#include "components/offline_pages/offline_page_item.h"
+#include "components/offline_pages/offline_page_model.h"
+#endif  // defined(OS_ANDROID)
 
 using content::BrowserContext;
 using content::BrowserThread;
@@ -32,6 +39,7 @@ using content::WebContents;
 using content::WebContentsObserver;
 using error_page::DnsProbeStatus;
 using error_page::DnsProbeStatusToString;
+using error_page::OfflinePageStatus;
 using ui::PageTransition;
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(chrome_browser_net::NetErrorTabHelper);
@@ -124,8 +132,8 @@ void NetErrorTabHelper::DidStartProvisionalLoadForFrame(
   is_error_page_ = is_error_page;
 
 #if defined(OS_ANDROID)
-  SetHasOfflinePages(render_frame_host);
-#endif
+  SetOfflinePageInfo(render_frame_host, validated_url);
+#endif  // defined(OS_ANDROID)
 }
 
 void NetErrorTabHelper::DidCommitProvisionalLoadForFrame(
@@ -177,7 +185,8 @@ bool NetErrorTabHelper::OnMessageReceived(
                         RunNetworkDiagnostics)
 #if defined(OS_ANDROID)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_ShowOfflinePages, ShowOfflinePages)
-#endif
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_LoadOfflineCopy, LoadOfflineCopy)
+#endif  // defined(OS_ANDROID)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
@@ -286,23 +295,66 @@ void NetErrorTabHelper::RunNetworkDiagnosticsHelper(
 }
 
 #if defined(OS_ANDROID)
-void NetErrorTabHelper::SetHasOfflinePages(
-  content::RenderFrameHost* render_frame_host) {
-  DCHECK(web_contents());
-  TabAndroid* tab = TabAndroid::FromWebContents(web_contents());
-  bool has_offline_pages = tab && tab->HasOfflinePages();
+void NetErrorTabHelper::SetOfflinePageInfo(
+    content::RenderFrameHost* render_frame_host, const GURL& url) {
+  // Bails out if offline pages not supported.
+  if (!offline_pages::IsOfflinePagesEnabled())
+    return;
+
+  offline_pages::OfflinePageModel* offline_page_model =
+      offline_pages::OfflinePageModelFactory::GetForBrowserContext(

[Lei Zhang, 2015/11/23 23:43:37]

Why are we doing a BrowserContext -> Profile -> BrowserContext dance? Does this
not work?

offline_pages::OfflinePageModel* offline_page_model =
    offline_pages::OfflinePageModelFactory::GetForBrowserContext(
        web_contents()->GetBrowserContext());

[jianli, 2015/11/23 23:49:50]

Thanks for catching this. Fixed.

+          Profile::FromBrowserContext(web_contents()->GetBrowserContext()));
+  if (!offline_page_model)
+    return;
+
+  OfflinePageStatus status = OfflinePageStatus::NONE;
+  if (offline_page_model->HasOfflinePages()) {
+    status = offline_page_model->GetPageByOnlineURL(url) ?
+        OfflinePageStatus::HAS_OFFLINE_PAGE :
+        OfflinePageStatus::HAS_OTHER_OFFLINE_PAGES;
+  }
   render_frame_host->Send(
-      new ChromeViewMsg_SetHasOfflinePages(
-          render_frame_host->GetRoutingID(),
-          has_offline_pages));
+      new ChromeViewMsg_SetOfflinePageInfo(
+          render_frame_host->GetRoutingID(), status));
 }
 
 void NetErrorTabHelper::ShowOfflinePages() {
+  // Makes sure that this is coming from from an error page.

[Lei Zhang, 2015/11/23 23:43:37]

nit: from from, ditto elsewhere in this file.

[jianli, 2015/11/23 23:49:50]

Done.

+  if (!IsFromErrorPage())
+    return;
+
   DCHECK(web_contents());
   TabAndroid* tab = TabAndroid::FromWebContents(web_contents());
   if (tab)
     tab->ShowOfflinePages();
 }
-#endif
+
+void NetErrorTabHelper::LoadOfflineCopy(const GURL& url) {
+  // Makes sure that this is coming from from an error page.
+  if (!IsFromErrorPage())
+    return;
+
+  GURL validated_url(url);

[Lei Zhang, 2015/11/23 23:43:37]

Why do we need a copy of |url| ? Why not just check url.is_valid()?

[jianli, 2015/11/23 23:49:50]

This is introduced based on nasko's comment: Since this URL comes from the
renderer, it cannot be directly trusted. It needs to be validated first. The
pattern used is:

GURL validated_url(url);
if (validated_url.is_valid())
  // do whatever is correct for invalid URLs, here probably just return

+  if (!validated_url.is_valid())
+    return;
+
+  DCHECK(web_contents());

[Lei Zhang, 2015/11/23 23:43:37]

Not really needed. You'd know when the DCHECK fails because it'll just crash on
the next line.

[jianli, 2015/11/23 23:49:50]

Done.

+  if (validated_url != web_contents()->GetURL())
+    return;
+
+  TabAndroid* tab = TabAndroid::FromWebContents(web_contents());
+  if (tab)
+    tab->LoadOfflineCopy(url);
+}
+
+bool NetErrorTabHelper::IsFromErrorPage() const {
+  content::NavigationEntry* entry =
+      web_contents()->GetController().GetLastCommittedEntry();
+  if (!entry)

[Lei Zhang, 2015/11/23 23:43:37]

Squish this into:

return entry && (entry->GetPageType() == content::PAGE_TYPE_ERROR);

[jianli, 2015/11/23 23:49:50]

Done.

+    return false;
+  return entry->GetPageType() == content::PAGE_TYPE_ERROR;
+}
+
+#endif  // defined(OS_ANDROID)
 
 }  // namespace chrome_browser_net