Move ExtensionCache to //extensions

extensions/shell/browser/shell_extensions_browser_client.h

Index: extensions/shell/browser/shell_extensions_browser_client.h
diff --git a/extensions/shell/browser/shell_extensions_browser_client.h b/extensions/shell/browser/shell_extensions_browser_client.h
index e5e985cfe73950b21ebf1de96e980561ff207d39..23ede3eb39af53bfef74b055b65c9b7d660fafa8 100644
--- a/extensions/shell/browser/shell_extensions_browser_client.h
+++ b/extensions/shell/browser/shell_extensions_browser_client.h
@@ -78,6 +78,7 @@ class ShellExtensionsBrowserClient : public ExtensionsBrowserClient {
       const std::string& event_name,
       scoped_ptr<base::ListValue> args) override;
   virtual net::NetLog* GetNetLog() override;
+  virtual ExtensionCache* GetExtensionCache() override;
 
  private:
   // The single BrowserContext for app_shell. Not owned.
@@ -89,6 +90,9 @@ class ShellExtensionsBrowserClient : public ExtensionsBrowserClient {
   // The PrefService for |browser_context_|.
   scoped_ptr<PrefService> prefs_;
 
+  // The extension cache used for download and installation.
+  scoped_ptr<ExtensionCache> extension_cache_;
+
   DISALLOW_COPY_AND_ASSIGN(ShellExtensionsBrowserClient);
 };