Move SessionStorageNamespace entirely into NavigationController and support StoragePartitions.

chrome/browser/instant/instant_controller.cc

 // Copyright (c) 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/instant/instant_controller.h"
 
 #include "base/command_line.h"
 #include "base/i18n/case_conversion.h"
 #include "base/metrics/histogram.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
@@ skipping 61 matching lines @@
       PREVIEW_NUM_TYPES + 1, base::Histogram::kUmaTargetedHistogramFlag);
   histogram->Add(usage);
 }
 
 void AddSessionStorageHistogram(InstantController::Mode mode,
                                 const TabContents* tab1,
                                 const TabContents* tab2) {
   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
 
 InstantController::InstantController(InstantControllerDelegate* delegate,
                                      Mode mode)
     : delegate_(delegate),
       mode_(mode),
       last_active_tab_(NULL),
       last_verbatim_(false),
@@ skipping 485 matching lines @@
     return false;
   }
 
   return true;
 }
 
 bool InstantController::IsOutOfDate() const {
   return !last_active_tab_ ||
          last_active_tab_ != delegate_->GetActiveTabContents();
 }