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

chrome/browser/profile.h

Index: chrome/browser/profile.h
diff --git a/chrome/browser/profile.h b/chrome/browser/profile.h
index 4dc3f5b0f1537a4de7dbb78befc57f29f6c0c43d..d876d8c87aeb86b7518b544e904c9a1f4285f884 100644
--- a/chrome/browser/profile.h
+++ b/chrome/browser/profile.h
@@ -51,6 +51,7 @@ class ExtensionMessageService;
 class ExtensionsService;
 class FaviconService;
 class FilePath;
+class FileSystemHostContext;
 class FindBarState;
 class GeolocationContentSettingsMap;
 class GeolocationPermissionContext;
@@ -277,6 +278,9 @@ class Profile {
   // Returns the PersonalDataManager associated with this profile.
   virtual PersonalDataManager* GetPersonalDataManager() = 0;
 
+  // Returns the HTML5 FileSystemHostContext assigned to this profile.
+  virtual FileSystemHostContext* GetFileSystemHostContext() = 0;
+
   // Init our themes system.
   virtual void InitThemes() = 0;