[Search] Store and recall search terms using NavigationEntry to improve search term extraction

chrome/browser/ui/search/search.cc

Index: chrome/browser/ui/search/search.cc
diff --git a/chrome/browser/ui/search/search.cc b/chrome/browser/ui/search/search.cc
index 796edb4ee64bf23013c73c455ea65b7d8c84b63d..71123712d5c49c13e2c29e173848483e8cc3e6ab 100644
--- a/chrome/browser/ui/search/search.cc
+++ b/chrome/browser/ui/search/search.cc
@@ -12,6 +12,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
+#include "content/public/browser/navigation_entry.h"
 
 #if !defined(OS_ANDROID)
 #include "chrome/browser/themes/theme_service.h"
@@ -46,6 +47,9 @@ const char kDisablingSuffix[] = "DISABLED";
 namespace chrome {
 namespace search {
 
+// static
+const char kInstantExtendedSearchTermsKey[] = "search_terms";
+
 // Check whether or not the Extended API should be used on the given profile.
 bool IsInstantExtendedAPIEnabled(Profile* profile) {
   return EmbeddedSearchPageVersion(profile) != 0;
@@ -139,6 +143,13 @@ void EnableQueryExtractionForTesting() {
 #endif
 }
 
+string16 GetSearchTermsFromNavigationEntry(
+    const content::NavigationEntry* entry) {
+  string16 search_terms;
+  entry->GetExtraData(kInstantExtendedSearchTermsKey, &search_terms);
+  return search_terms;
+}
+
 bool IsForcedInstantURL(const GURL& url) {
   CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (!command_line->HasSwitch(switches::kInstantURL))