Revert "Move ExtensionCache to //extensions"

chrome/browser/extensions/updater/extension_cache.h

Index: chrome/browser/extensions/updater/extension_cache.h
diff --git a/extensions/browser/updater/extension_cache.h b/chrome/browser/extensions/updater/extension_cache.h
similarity index 82%
rename from extensions/browser/updater/extension_cache.h
rename to chrome/browser/extensions/updater/extension_cache.h
index f6bdb02ca554f6e9b60cbf6118029ee6348786c5..edcc1fa3d3ec91f75993859578c0f9f6f8b11100 100644
--- a/extensions/browser/updater/extension_cache.h
+++ b/chrome/browser/extensions/updater/extension_cache.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef EXTENSIONS_BROWSER_UPDATER_EXTENSION_CACHE_H_
-#define EXTENSIONS_BROWSER_UPDATER_EXTENSION_CACHE_H_
+#ifndef CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_CACHE_H_
+#define CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_CACHE_H_
 
 #include <string>
 
@@ -16,13 +16,13 @@ namespace extensions {
 // between multiple users and profiles on the machine.
 class ExtensionCache {
  public:
+  // Return global singleton instance of ExtensionCache.
+  static ExtensionCache* GetInstance();
+
   // Callback that is invoked when the file placed when PutExtension done.
   typedef base::Callback<void(const base::FilePath& file_path,
                               bool file_ownership_passed)> PutExtensionCallback;
 
-  ExtensionCache() {}
-  virtual ~ExtensionCache() {}
-
   // Initialize cache in background. The |callback| is called when cache ready.
   // Can be called multiple times. The |callback| can be called immediately if
   // cache is ready.
@@ -54,10 +54,14 @@ class ExtensionCache {
                             const std::string& version,
                             const PutExtensionCallback& callback) = 0;
 
- private:
-  DISALLOW_COPY_AND_ASSIGN(ExtensionCache);
+ protected:
+  virtual ~ExtensionCache() {}
+
+  // Sets the singleton to the given |cache|. Returns the previous value of
+  // the singleton. Ownership is not transferred.
+  static ExtensionCache* SetForTesting(ExtensionCache* cache);
 };
 
 }  // namespace extensions
 
-#endif  // EXTENSIONS_BROWSER_UPDATER_EXTENSION_CACHE_H_
+#endif  // CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_CACHE_H_