Revert 244407 "InstantExtended: remove dead code related to the ..."

trunk/src/chrome/browser/search/search.cc

Index: trunk/src/chrome/browser/search/search.cc
===================================================================
--- trunk/src/chrome/browser/search/search.cc	(revision 244428)
+++ trunk/src/chrome/browser/search/search.cc	(working copy)
@@ -7,6 +7,7 @@
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/prefs/pref_service.h"
+#include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversions.h"
@@ -58,7 +59,13 @@
 const uint64 kEmbeddedPageVersionDefault = 2;
 #endif
 
+// The staleness timeout can be set (in seconds) via this config.
+const char kStalePageTimeoutFlagName[] = "stale";
+const int kStalePageTimeoutDefault = 3 * 3600;  // 3 hours.
+
 const char kHideVerbatimFlagName[] = "hide_verbatim";
+const char kShowNtpFlagName[] = "show_ntp";
+const char kUseCacheableNTP[] = "use_cacheable_ntp";
 const char kPrefetchSearchResultsFlagName[] = "prefetch_results";
 const char kPrefetchSearchResultsOnSRP[] = "prefetch_results_srp";
 const char kDisplaySearchButtonFlagName[] = "display_search_button";
@@ -388,9 +395,14 @@
   if (entry->GetURL() == GetLocalInstantURL(profile))
     return true;
 
-  GURL new_tab_url(GetNewTabPageURL(profile));
-  return new_tab_url.is_valid() &&
-      search::MatchesOriginAndPath(entry->GetURL(), new_tab_url);
+  if (ShouldUseCacheableNTP()) {
+    GURL new_tab_url(GetNewTabPageURL(profile));
+    return new_tab_url.is_valid() &&
+        search::MatchesOriginAndPath(entry->GetURL(), new_tab_url);
+  }
+
+  return IsInstantURL(entry->GetVirtualURL(), profile) &&
+      GetSearchTermsImpl(contents, entry).empty();
 }
 
 bool IsSuggestPrefEnabled(Profile* profile) {
@@ -446,6 +458,9 @@
 }
 
 GURL GetNewTabPageURL(Profile* profile) {
+  if (!ShouldUseCacheableNTP())
+    return GURL();
+
   if (!profile || profile->IsOffTheRecord())
     return GURL();
 
@@ -473,6 +488,9 @@
 }
 
 bool ShouldPrefetchSearchResults() {
+  if (!ShouldUseCacheableNTP())
+    return false;
+
   FieldTrialFlags flags;
   return GetFieldTrialInfo(&flags) && GetBoolValueForFlagWithDefault(
       kPrefetchSearchResultsFlagName, false, flags);
@@ -488,6 +506,23 @@
       kHideVerbatimFlagName, false, flags);
 }
 
+bool ShouldUseCacheableNTP() {
+  FieldTrialFlags flags;
+  return !GetFieldTrialInfo(&flags) || GetBoolValueForFlagWithDefault(
+      kUseCacheableNTP, true, flags);
+}
+
+bool ShouldShowInstantNTP() {
+  // If using the cacheable NTP, load the NTP directly instead of preloading its
+  // contents using InstantNTP.
+  if (ShouldUseCacheableNTP())
+    return false;
+
+  FieldTrialFlags flags;
+  return !GetFieldTrialInfo(&flags) ||
+      GetBoolValueForFlagWithDefault(kShowNtpFlagName, true, flags);
+}
+
 DisplaySearchButtonConditions GetDisplaySearchButtonConditions() {
   const CommandLine* cl = CommandLine::ForCurrentProcess();
   if (cl->HasSwitch(switches::kDisableSearchButtonInOmnibox)) {
@@ -570,6 +605,43 @@
   return effective_url;
 }
 
+int GetInstantLoaderStalenessTimeoutSec() {
+  int timeout_sec = kStalePageTimeoutDefault;
+  FieldTrialFlags flags;
+  if (GetFieldTrialInfo(&flags)) {
+    timeout_sec = GetUInt64ValueForFlagWithDefault(kStalePageTimeoutFlagName,
+                                                   kStalePageTimeoutDefault,
+                                                   flags);
+  }
+
+  // Require a minimum 5 minute timeout.
+  if (timeout_sec < 0 || (timeout_sec > 0 && timeout_sec < 300))
+    timeout_sec = kStalePageTimeoutDefault;
+
+  // Randomize by upto 15% either side.
+  timeout_sec = base::RandInt(timeout_sec * 0.85, timeout_sec * 1.15);
+
+  return timeout_sec;
+}
+
+bool IsPreloadedInstantExtendedNTP(const content::WebContents* contents) {
+  if (!IsInstantExtendedAPIEnabled())
+    return false;
+
+  ProfileManager* profile_manager = g_browser_process->profile_manager();
+  if (!profile_manager)
+    return false;  // The profile manager can be NULL while testing.
+
+  const std::vector<Profile*>& profiles = profile_manager->GetLoadedProfiles();
+  for (size_t i = 0; i < profiles.size(); ++i) {
+    const InstantService* instant_service =
+        InstantServiceFactory::GetForProfile(profiles[i]);
+    if (instant_service && instant_service->GetNTPContents() == contents)
+      return true;
+  }
+  return false;
+}
+
 bool HandleNewTabURLRewrite(GURL* url,
                             content::BrowserContext* browser_context) {
   if (!IsInstantExtendedAPIEnabled())