Fix chromium-style compile error that got in the tree since yesterday.

chrome/browser/extensions/extension_special_storage_policy.h

Index: chrome/browser/extensions/extension_special_storage_policy.h
diff --git a/chrome/browser/extensions/extension_special_storage_policy.h b/chrome/browser/extensions/extension_special_storage_policy.h
index 72ab89b8987272129908abd2e581b5e15891c3e3..34c42671f802b4cd2cf2224485c630d9408be90b 100644
--- a/chrome/browser/extensions/extension_special_storage_policy.h
+++ b/chrome/browser/extensions/extension_special_storage_policy.h
@@ -20,6 +20,8 @@ class Extension;
 // to determine which origins have these rights.
 class ExtensionSpecialStoragePolicy : public quota::SpecialStoragePolicy {
  public:
+  ExtensionSpecialStoragePolicy();
+
   // SpecialStoragePolicy methods used by storage subsystems and the browsing
   // data remover. These methods are safe to call on any thread.
   virtual bool IsStorageProtected(const GURL& origin);
@@ -31,8 +33,14 @@ class ExtensionSpecialStoragePolicy : public quota::SpecialStoragePolicy {
   void RevokeRightsForAllExtensions();
 
  private:
+  friend class base::RefCountedThreadSafe<SpecialStoragePolicy>;
+  virtual ~ExtensionSpecialStoragePolicy();
+
   class SpecialCollection {
    public:
+    SpecialCollection();
+    ~SpecialCollection();
+
     bool Contains(const GURL& origin);
     void Add(const Extension* extension);
     void Remove(const Extension* extension);