Extract Drive related code to drive::MountPointProviderDelegate.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index f2a6ab4bf29144cdaa5fdf843c2bbb6ac41fbe9a..bb1c9c9fa9e44fef1618d11890bb0ed235a9c8fa 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -148,6 +148,7 @@
 #include "chrome/browser/spellchecker/spellcheck_message_filter_mac.h"
 #elif defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/chrome_browser_main_chromeos.h"
+#include "chrome/browser/chromeos/drive/mount_point_provider_delegate.h"
 #include "chrome/browser/chromeos/fileapi/cros_mount_point_provider.h"
 #include "chrome/browser/chromeos/login/startup_utils.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
@@ -2311,6 +2312,7 @@ void ChromeContentBrowserClient::GetAdditionalFileSystemMountPointProviders(
   DCHECK(external_mount_points);
   chromeos::CrosMountPointProvider* cros_mount_provider =
       new chromeos::CrosMountPointProvider(
+          new drive::MountPointProviderDelegate(external_mount_points),
           special_storage_policy,
           external_mount_points,
           fileapi::ExternalMountPoints::GetSystemInstance());