Move SessionStorageNamespace entirely into NavigationController and support StoragePartitions.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 0e96a038652dac1f6ec0afeaa81b3b7fa1fc820b..a84c6dcc4d35c2b6447452f43081fce7d9f5be0e 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -161,11 +161,25 @@ net::URLRequestContext* ContentBrowserClient::OverrideRequestContextForURL(
 }
 
 std::string ContentBrowserClient::GetStoragePartitionIdForChildProcess(
-    content::BrowserContext* browser_context,
+    BrowserContext* browser_context,
     int child_process_id) {
   return std::string();
 }
 
+std::string ContentBrowserClient::GetStoragePartitionIdForSiteInstance(
+    BrowserContext* browser_context,
+    content::SiteInstance* instance) {
+  return std::string();
+}
+
+bool ContentBrowserClient::IsValidStoragePartitionId(
+    BrowserContext* browser_context,
+    const std::string& partition_id) {
+  // Since the GetStoragePartitionIdForChildProcess() only generates empty
+  // strings, we should only ever see empty strings coming back.
+  return partition_id.empty();
+}
+
 MediaObserver* ContentBrowserClient::GetMediaObserver() {
   return NULL;
 }