Fall back to local page if online NTP fails to load.

chrome/browser/search/search.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/search/search.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
@@ skipping 142 matching lines @@
 bool IsInstantURL(const GURL& url, Profile* profile) {
   TemplateURL* template_url = GetDefaultSearchProviderTemplateURL(profile);
   if (!template_url)
     return false;
 
   const TemplateURLRef& instant_url_ref = template_url->instant_url_ref();
   const bool extended_api_enabled = IsInstantExtendedAPIEnabled();
   GURL effective_url = url;
 
   if (IsCommandLineInstantURL(url))
-    effective_url = CoerceCommandLineURLToTemplateURL(url, instant_url_ref,
-                                                      kDisableStartMargin);
+    return true;

[sreeram, 2013/05/03 23:17:31]

This bypasses the secure & espv checks. I understand your argument that "if
IsCommandLineInstantURL, it must be IsInstantURL!". But that's not what this is
exactly meant to be. The --instant-url is meant to be a very light-weight way to
change the template's instant URL. In particular, I want it to go through as
many of the same checks we apply to the regular template URL.

In fact, by leaving the code as is (without your change), you are now forced to
test the 404/204 case properly. I.e., bring up a google.com server that actually
serves a 204 on the expected /search or /webhp path. Because, that's what users
will actually experience. By allowing this shortcut, you can "get away" with
testing --instant-url="file://foo/bar", which doesn't really show that this
would work for the normal user case.

[David Black, 2013/05/04 00:49:23]

As discussed in person, I maintain the logic here as-is is extremely confusing,
but reverted back to what it was since it's not critical for this CL.

 
   if (!effective_url.is_valid())
     return false;
 
   if (extended_api_enabled && !effective_url.SchemeIsSecure())
     return false;
 
   if (extended_api_enabled &&
       !template_url->HasSearchTermsReplacementKey(effective_url))
     return false;
@@ skipping 297 matching lines @@
 
 bool IsInstantEnabled(Profile* profile) {
   return GetInstantURL(profile, kDisableStartMargin).is_valid();
 }
 
 bool ShouldPreferRemoteNTPOnStartup() {
   // Check the command-line/about:flags setting first, which should have
   // precedence and allows the trial to not be reported (if it's never queried).
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kDisableInstantExtendedAPI) ||
-      command_line->HasSwitch(switches::kEnableInstantExtendedAPI) ||
       command_line->HasSwitch(switches::kEnableLocalOnlyInstantExtendedAPI) ||
-      command_line->HasSwitch(switches::kDisableLocalOnlyInstantExtendedAPI)) {
+      command_line->HasSwitch(switches::kDisableLocalFirstLoadNTP)) {
     return false;
   }
+  if (command_line->HasSwitch(switches::kEnableLocalFirstLoadNTP))
+    return true;

[sreeram, 2013/05/03 23:17:31]

This is inverted. kEnableLocalFirstLoadNTP should "return false" and
kDisableLocalFirstLoadNTP should "return true".

[David Black, 2013/05/04 00:49:23]

Whoops.  Fixed.

 
   FieldTrialFlags flags;
   if (GetFieldTrialInfo(
           base::FieldTrialList::FindFullName(kInstantExtendedFieldTrialName),
           &flags, NULL)) {
     return GetBoolValueForFlagWithDefault(kUseRemoteNTPOnStartupFlagName, false,
                                           flags);
   }
   return false;
 }
@@ skipping 105 matching lines @@
 
   GURL instant_url = TemplateURLRefToGURL(template_url->instant_url_ref(),
                                           kDisableStartMargin);
   // Extended mode instant requires a search terms replacement key.
   return instant_url.is_valid() &&
          (!IsInstantExtendedAPIEnabled() ||
           template_url->HasSearchTermsReplacementKey(instant_url));
 }
 
 }  // namespace chrome