Viewing cached webpages while offline is not available on Chrome OS

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 38d22decc15838961c4b8b93cec03d217da30aab..83ea305a3b981b83c72e6eed2d7962b9e066af3c 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -259,6 +259,10 @@ const char kDisableIPv6[]                   = "disable-ipv6";
 const char kDisableMinimizeOnSecondLauncherItemClick[] =
     "disable-minimize-on-second-launcher-item-click";
 
+// Disables the new offline error page generated by NetErrorHelper for ChromeOS
+// and instead uses the old error page generated by OfflineResourceThrottle.
+const char kDisableNewOfflineErrorPage[] = "disable-new-offline-error-page";
+
 // Disables the menu on the NTP for accessing sessions from other devices.
 const char kDisableNTPOtherSessionsMenu[]   = "disable-ntp-other-sessions-menu";
 
@@ -1372,6 +1376,16 @@ bool SettingsWindowEnabled() {
 #endif
 }
 
+// Will return true as a default value if the "disable-new-offline-error-page"
+// command-line switch is not available.

[Randy Smith (Not in Mondays), 2015/01/27 19:05:29]

I'm confused by this.  Maybe I just haven't been following the discussion on the
CL closely enough, but it seems to me if you're worried about unexpected
consequences leading to your wanting to fall back to the old behavior, you'd
want to hook that into a finch trial, so it could be turned off without action
on the users' part and without a new release of ChromeOS.  What am I missing?

[oshima, 2015/01/27 22:41:31]

Finch is for A/B testing, which is used to make decision which UI is better. We
definitely want to switch to the common page. This is to make it easy to turn
off and/or troubleshoot if we find a problem with it during beta testing.

[Randy Smith (Not in Mondays), 2015/01/27 23:52:59]

That's not the only thing finch is used for; it's also used as a centrally
controllable way to turn off features if they start misbehaving, or to launch
features gradually (1%->10%->100%).  I've definitely used it the second way, and
I've relied on being able to use it the first way.  Having said that, if you're
comfortable the risk of problems once it reaches the field is low, skipping it
is good by me--it's a bit of a pain to setup.

+bool NewOfflineErrorPageEnabled() {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+      ::switches::kDisableNewOfflineErrorPage))

[oshima, 2015/01/27 22:41:31]

You can just return

return !.. HasSwitch()

+    return false;
+
+  return true;
+}
+
 #if defined(OS_CHROMEOS)
 bool PowerOverlayEnabled() {
   return base::CommandLine::ForCurrentProcess()->HasSwitch(