Move SessionStorageNamespace entirely into NavigationController and support StoragePartitions.

chrome/browser/instant/instant_controller.cc

Index: chrome/browser/instant/instant_controller.cc
diff --git a/chrome/browser/instant/instant_controller.cc b/chrome/browser/instant/instant_controller.cc
index 2eefd0670edbc69df96796eeda0d7b2ef7730152..7454d817bcf3aa1af633a6cdeb57f5c4af5e4d15 100644
--- a/chrome/browser/instant/instant_controller.cc
+++ b/chrome/browser/instant/instant_controller.cc
@@ -79,9 +79,29 @@ void AddSessionStorageHistogram(InstantController::Mode mode,
   base::Histogram* histogram = base::BooleanHistogram::FactoryGet(
       "Instant.SessionStorageNamespace" + ModeToString(mode),
       base::Histogram::kUmaTargetedHistogramFlag);
-  histogram->AddBoolean(
-      tab1->web_contents()->GetController().GetSessionStorageNamespace() ==
-      tab2->web_contents()->GetController().GetSessionStorageNamespace());
+  const content::SessionStorageNamespaceMap& session_storage_map1 =
+      tab1->web_contents()->GetController().GetSessionStorageNamespaceMap();
+  const content::SessionStorageNamespaceMap& session_storage_map2 =
+      tab2->web_contents()->GetController().GetSessionStorageNamespaceMap();
+  bool is_session_storage_the_same =
+      session_storage_map1.size() == session_storage_map2.size();
+  if (is_session_storage_the_same) {
+    // The size is the same, so let's check that all entries match.
+    for (content::SessionStorageNamespaceMap::const_iterator it1 =
+             session_storage_map1.begin();
+         it1 != session_storage_map1.end();
+         ++it1) {
+
+      content::SessionStorageNamespaceMap::const_iterator it2 =
+          session_storage_map2.find(it1->first);

[sreeram, 2012/08/09 19:20:05]

Since the map is a std::map, with string keys, iteration order is well defined.
So why not just iterate them both in parallel, checking that the keys and values
are the same?

+      if (it2 == session_storage_map2.end() ||
+          it1->second != it2->second) {
+        is_session_storage_the_same = false;
+        break;
+      }
+    }
+  }
+  histogram->AddBoolean(is_session_storage_the_same);
 }
 
 }  // namespace