Use ExtractDrivePath(path()) instead of virtual_path() for getting Drive path.

chrome/browser/chromeos/drive/drive_file_system_util.h

Index: chrome/browser/chromeos/drive/drive_file_system_util.h
diff --git a/chrome/browser/chromeos/drive/drive_file_system_util.h b/chrome/browser/chromeos/drive/drive_file_system_util.h
index ddb1b603abc2415e5c83d3c88e701c22c3689d6d..28feb9190c1fad56d17ad9cef3712cdec8017940 100644
--- a/chrome/browser/chromeos/drive/drive_file_system_util.h
+++ b/chrome/browser/chromeos/drive/drive_file_system_util.h
@@ -12,6 +12,7 @@
 #include "chrome/browser/chromeos/drive/drive_file_error.h"
 #include "chrome/browser/google_apis/gdata_errorcode.h"
 #include "googleurl/src/gurl.h"
+#include "webkit/fileapi/file_system_url.h"
 
 class Profile;
 
@@ -112,9 +113,14 @@ base::FilePath ConvertToMyDriveNamespace(const base::FilePath& path);
 
 // Extracts the Drive path from the given path located under the Drive mount
 // point. Returns an empty path if |path| is not under the Drive mount point.
-// Examples: ExtractGDatPath("/special/drive/foo.txt") => "drive/foo.txt"
+// Examples: ExtractDrivePath("/special/drive/foo.txt") => "drive/foo.txt"
 base::FilePath ExtractDrivePath(const base::FilePath& path);
 
+// Extracts the Drive path (e.g., "drive/foo.txt") from the filesystem URL.
+// Returns an empty path if |url| does not point under Drive mount point.
+base::FilePath ExtractDrivePathFromFileSystemUrl(
+    const fileapi::FileSystemURL& url);
+
 // Escapes a file name in Drive cache.
 // Replaces percent ('%'), period ('.') and slash ('/') with %XX (hex)
 std::string EscapeCacheFileName(const std::string& filename);