Persist offline page info in a navigation entry if needed

components/sessions/content/content_serialized_navigation_builder.cc

Index: components/sessions/content/content_serialized_navigation_builder.cc
diff --git a/components/sessions/content/content_serialized_navigation_builder.cc b/components/sessions/content/content_serialized_navigation_builder.cc
index 59df5cc2d016730fa5a64ff1c9875b12ad3cd696..90829d5131504482211a6bb6c23be85d1cf6f438 100644
--- a/components/sessions/content/content_serialized_navigation_builder.cc
+++ b/components/sessions/content/content_serialized_navigation_builder.cc
@@ -4,6 +4,9 @@
 
 #include "components/sessions/content/content_serialized_navigation_builder.h"
 
+#include "base/macros.h"
+#include "base/strings/string_tokenizer.h"
+#include "base/strings/string_util.h"
 #include "components/sessions/content/content_record_password_state.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "content/public/browser/browser_context.h"
@@ -15,6 +18,37 @@
 
 namespace sessions {
 
+namespace {
+
+const char kOfflinePageHeader[] = "X-Chrome-offline: ";
+
+// Returns the offline page info that needs to be persisted, based on extra
+// headers.
+// TODO(jianli): Move this logic to components/offline_pages/request.
+std::string GetOfflinePageInfo(const content::NavigationEntry& entry) {
+  std::string extra_headers = entry.GetExtraHeaders();
+  if (extra_headers.empty())
+    return std::string();
+  // The offline header will be the only extra header if it is present.
+  if (!base::StartsWith(extra_headers,
+                        kOfflinePageHeader,
+                        base::CompareCase::INSENSITIVE_ASCII)) {
+    return std::string();
+  }
+  std::string value = extra_headers.substr(arraysize(kOfflinePageHeader) - 1);
+  if (value.find("\n") != std::string::npos) {
+    return std::string();
+  }
+  base::StringTokenizer tokenizer(value, ", ");
+  while (tokenizer.GetNext()) {
+    if (tokenizer.token() == "persist=1")
+      return value;
+  }
+  return std::string();
+}
+
+}  // namespace
+
 // static
 SerializedNavigationEntry
 ContentSerializedNavigationBuilder::FromNavigationEntry(
@@ -41,6 +75,7 @@ ContentSerializedNavigationBuilder::FromNavigationEntry(
   navigation.http_status_code_ = entry.GetHttpStatusCode();
   navigation.redirect_chain_ = entry.GetRedirectChain();
   navigation.password_state_ = GetPasswordStateFromNavigation(entry);
+  navigation.offline_page_info_ = GetOfflinePageInfo(entry);
 
   return navigation;
 }
@@ -53,6 +88,11 @@ ContentSerializedNavigationBuilder::ToNavigationEntry(
     content::BrowserContext* browser_context) {
   blink::WebReferrerPolicy policy =
       static_cast<blink::WebReferrerPolicy>(navigation->referrer_policy_);
+  // The extra headers, except the one used for offline page support, are not
+  // sync'ed across sessions.
+  std::string extra_headers;
+  if (!navigation->offline_page_info_.empty())
+    extra_headers = kOfflinePageHeader + navigation->offline_page_info_;
   std::unique_ptr<content::NavigationEntry> entry(
       content::NavigationController::CreateNavigationEntry(
           navigation->virtual_url_,
@@ -62,8 +102,7 @@ ContentSerializedNavigationBuilder::ToNavigationEntry(
           // Use a transition type of reload so that we don't incorrectly
           // increase the typed count.
           ui::PAGE_TRANSITION_RELOAD, false,
-          // The extra headers are not sync'ed across sessions.
-          std::string(), browser_context));
+          extra_headers, browser_context));
 
   entry->SetTitle(navigation->title_);
   entry->SetPageState(content::PageState::CreateFromEncodedData(