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

chrome/browser/sessions/session_types.cc

Index: chrome/browser/sessions/session_types.cc
diff --git a/chrome/browser/sessions/session_types.cc b/chrome/browser/sessions/session_types.cc
index 59afc341fdb9604100636d2befdc8f85c738cddf..8457e66ef569ab5f91dd9ebcfd069caa02de8a8c 100644
--- a/chrome/browser/sessions/session_types.cc
+++ b/chrome/browser/sessions/session_types.cc
@@ -9,6 +9,7 @@
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
+#include "chrome/browser/instant/instant_controller.h"
 #include "chrome/browser/sessions/session_command.h"
 #include "chrome/browser/ui/browser.h"
 #include "content/public/browser/navigation_controller.h"
@@ -48,6 +49,9 @@ TabNavigation TabNavigation::FromNavigationEntry(
   navigation.original_request_url_ = entry.GetOriginalRequestURL();
   navigation.is_overriding_user_agent_ = entry.GetIsOverridingUserAgent();
   navigation.timestamp_ = entry.GetTimestamp();
+  entry.GetExtraData(std::string(InstantController::kSearchTermsKey),
+                     &navigation.search_terms_);
+
   return navigation;
 }
 
@@ -132,6 +136,7 @@ TabNavigation TabNavigation::FromSyncData(
       static_cast<content::PageTransition>(transition);
 
   navigation.timestamp_ = base::Time();
+  navigation.search_terms_ = UTF8ToUTF16(sync_data.search_terms());
 
   return navigation;
 }
@@ -201,6 +206,7 @@ enum TypeMask {
 // original_request_url_
 // is_overriding_user_agent_
 // timestamp_
+// search_terms_
 
 void TabNavigation::WriteToPickle(Pickle* pickle) const {
   pickle->WriteInt(index_);
@@ -245,6 +251,8 @@ void TabNavigation::WriteToPickle(Pickle* pickle) const {
       original_request_url_.spec() : std::string());
   pickle->WriteBool(is_overriding_user_agent_);
   pickle->WriteInt64(timestamp_.ToInternalValue());
+
+  WriteString16ToPickle(pickle, &bytes_written, max_state_size, search_terms_);
 }
 
 bool TabNavigation::ReadFromPickle(PickleIterator* iterator) {
@@ -298,6 +306,10 @@ bool TabNavigation::ReadFromPickle(PickleIterator* iterator) {
     } else {
       timestamp_ = base::Time();
     }
+
+    // If the search terms field can't be found, leave it empty.
+    if (!iterator->ReadString16(&search_terms_))
+      search_terms_ = string16();
   }
 
   return true;
@@ -326,6 +338,7 @@ scoped_ptr<NavigationEntry> TabNavigation::ToNavigationEntry(
   entry->SetOriginalRequestURL(original_request_url_);
   entry->SetIsOverridingUserAgent(is_overriding_user_agent_);
   entry->SetTimestamp(timestamp_);
+  entry->SetExtraData(InstantController::kSearchTermsKey, search_terms_);
 
   return entry.Pass();
 }
@@ -418,6 +431,8 @@ sync_pb::TabNavigation TabNavigation::ToSyncData() const {
   // The full-resolution timestamp works as a global ID.
   sync_data.set_global_id(timestamp_.ToInternalValue());
 
+  sync_data.set_search_terms(UTF16ToUTF8(search_terms_));
+
   return sync_data;
 }