(2nd try) Add a helper class that keeps per-profile information for FileSystem API

chrome/browser/file_system/file_system_dispatcher_host.h

Index: chrome/browser/file_system/file_system_dispatcher_host.h
diff --git a/chrome/browser/file_system/file_system_dispatcher_host.h b/chrome/browser/file_system/file_system_dispatcher_host.h
index f756ebef224f7b3614354b38bbf25312f73f8c07..0f8b63ad2e7e54e9a24a80df30fb5a3e929e8c6e 100644
--- a/chrome/browser/file_system/file_system_dispatcher_host.h
+++ b/chrome/browser/file_system/file_system_dispatcher_host.h
@@ -11,6 +11,7 @@
 #include "base/ref_counted.h"
 #include "chrome/common/render_messages.h"
 
+class FileSystemHostContext;
 class HostContentSettingsMap;
 class Receiver;
 class ResourceMessageFilter;
@@ -19,6 +20,7 @@ class FileSystemDispatcherHost
     : public base::RefCountedThreadSafe<FileSystemDispatcherHost> {
  public:
   FileSystemDispatcherHost(IPC::Message::Sender* sender,
+                           FileSystemHostContext* file_system_host_context,
                            HostContentSettingsMap* host_content_settings_map);
   void Init(base::ProcessHandle process_handle);
   void Shutdown();
@@ -46,6 +48,8 @@ class FileSystemDispatcherHost
 
   bool shutdown_;
 
+  scoped_refptr<FileSystemHostContext> context_;
+
   // Used to look up permissions.
   scoped_refptr<HostContentSettingsMap> host_content_settings_map_;
 };