Drop prefixes from test data resource IDs

These prefixes were only available in IDs aquired with the old API.

BUG=None
TEST=git cl try

Review URL: https://codereview.chromium.org/439713003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287322 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/chromeos/drive/file_cache_unittest.cc b/chrome/browser/chromeos/drive/file_cache_unittest.cc
index 8fcd6cad..03a0c3b6 100644
--- a/chrome/browser/chromeos/drive/file_cache_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_cache_unittest.cc
@@ -537,7 +537,7 @@
 }
 
 TEST_F(FileCacheTest, ClearAll) {
-  const std::string id("pdf:1a2b");
+  const std::string id("1a2b");
   const std::string md5("abcdef0123456789");
 
   // Store an existing file.