Load live version when reloading an offline page on connected network

chrome/browser/android/offline_pages/offline_page_tab_helper.cc

Index: chrome/browser/android/offline_pages/offline_page_tab_helper.cc
diff --git a/chrome/browser/android/offline_pages/offline_page_tab_helper.cc b/chrome/browser/android/offline_pages/offline_page_tab_helper.cc
index 0b31e810fe92a55927db70c03a82d99744604963..39486a553a371036fc9fc8341045787a46c5820e 100644
--- a/chrome/browser/android/offline_pages/offline_page_tab_helper.cc
+++ b/chrome/browser/android/offline_pages/offline_page_tab_helper.cc
@@ -37,11 +37,20 @@ void OfflinePageTabHelper::DidStartNavigation(
   if (!navigation_handle->IsInMainFrame())
     return;
 
+  // If the navigation is referencing fragment (synchronous navigation could
+  // only be referencing fragment navigation or pushState/popState navigation,
+  // while the latter is unlikely because offline page disables Javascript
+  // execution), do not reset out cached offline info.
+  if (navigation_handle->IsSynchronousNavigation())

[Dmitry Titov, 2016/09/17 02:22:54]

As discussed, lets keep the IsSamePage() check in DidFinishNamvigation, and not
use IsSynchronousNavigation. 

So I think the best approach here is:
0. Have provisional values for page, header, is_offline_preview.
1. Clear provisional values in DidStartNavigation
2. Most of the time (but not always) Interceptor will chime in with
SetOfflinePage and set provisional values
3. In DidFinishNavigation, if not IsSamePage, do real_values <-
provisional-values.

This works in many combinations when some callbacks are missing/repeated, and is
more direct.

[jianli, 2016/09/19 21:29:05]

We also need to clear the real values here because otherwise the following bug
will be hit:
1) Open a downloaded page on connected network. The offline indicator should be
shown.
2) Manually type any other URL of a web site that could take a while to load.
The offline indicator will not be reset during loading.

+    return;
+
   // This is a new navigation so we can invalidate any previously scheduled
   // operations.
   weak_ptr_factory_.InvalidateWeakPtrs();
 
   provisional_offline_page_ = nullptr;
+  offline_page_ = nullptr;
+  offline_header_.Clear();
   is_offline_preview_ = false;
   reloading_url_on_net_error_ = false;
 }
@@ -55,9 +64,8 @@ void OfflinePageTabHelper::DidFinishNavigation(
   if (!navigation_handle->HasCommitted())
     return;
 
-  if (navigation_handle->IsSamePage()) {
+  if (navigation_handle->IsSynchronousNavigation())
     return;
-  }
 
   offline_page_ = std::move(provisional_offline_page_);
   provisional_offline_page_ = nullptr;
@@ -121,19 +129,20 @@ void OfflinePageTabHelper::SelectPageForOnlineURLDone(
   // Reloads the page with extra header set to force loading the offline page.
   content::NavigationController::LoadURLParams load_params(offline_page->url);
   load_params.transition_type = ui::PAGE_TRANSITION_RELOAD;
-  load_params.extra_headers = kOfflinePageHeader;
-  load_params.extra_headers += ":";
-  load_params.extra_headers += kOfflinePageHeaderReasonKey;
-  load_params.extra_headers += "=";
-  load_params.extra_headers += kOfflinePageHeaderReasonValueDueToNetError;
+  OfflinePageHeader offline_header;
+  offline_header.reason = OfflinePageHeader::Reason::NET_ERROR;
+  load_params.extra_headers = offline_header.GetCompleteHeaderString();
   web_contents()->GetController().LoadURLWithParams(load_params);
 }
 
 // This is a callback from network request interceptor. It happens between
 // DidStartNavigation and DidFinishNavigation calls on this tab helper.
-void OfflinePageTabHelper::SetOfflinePage(const OfflinePageItem& offline_page,
-                                          bool is_offline_preview) {
+void OfflinePageTabHelper::SetOfflinePage(
+    const OfflinePageItem& offline_page,
+    const OfflinePageHeader& offline_header,
+    bool is_offline_preview) {
   provisional_offline_page_ = base::MakeUnique<OfflinePageItem>(offline_page);
+  offline_header_ = offline_header;
   is_offline_preview_ = is_offline_preview;
 }