Don't assume sandbox_provider() handles all sandboxed filesystems

- Moves DeleteOriginDataOnFileThread() method to
  QuotaUtil interface (from SandboxMountPointProvider)
- Changes FileSystemContext::DeleteDataForOriginOnFileThread
  not to directly call sandbox_provider()->DeleteOriginDataOnFileThread
  but calls the QuotaUtil's DeleteOriginDataOnFileThread method
  if the provider returns non-null QuotaUtil.

More changes are coming, this is fixing the easiest part.

BUG=250791
TEST=unit_test:BrowsingDataFileSystemHelperTest.*

Review URL: https://chromiumcodereview.appspot.com/17083003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@206997 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/webkit/browser/fileapi/test_mount_point_provider.cc b/webkit/browser/fileapi/test_mount_point_provider.cc
index 14211f2e..fe05ceb46 100644
--- a/webkit/browser/fileapi/test_mount_point_provider.cc
+++ b/webkit/browser/fileapi/test_mount_point_provider.cc
@@ -33,6 +33,14 @@
   virtual ~QuotaUtil() {}
 
   // FileSystemQuotaUtil overrides.
+  virtual base::PlatformFileError DeleteOriginDataOnFileThread(
+      FileSystemContext* context,
+      quota::QuotaManagerProxy* proxy,
+      const GURL& origin_url,
+      FileSystemType type) OVERRIDE {
+    NOTREACHED();
+    return base::PLATFORM_FILE_OK;
+  }
   virtual void GetOriginsForTypeOnFileThread(
       FileSystemType type,
       std::set<GURL>* origins) OVERRIDE {