[PPAPI] Fixed FileSystems from JavaScript not having a context.

ppapi/tests/test_post_message.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/tests/test_post_message.h"
 
 #include <string.h>
 #include <algorithm>
 #include <map>
 #include <sstream>
@@ skipping 602 matching lines @@
   PP_Var var = message_data_.back().Detach();
   PP_Resource result = var_resource_interface_->VarToResource(var);
   ASSERT_TRUE(file_system_interface_->IsFileSystem(result));
   {
     pp::FileSystem file_system(pp::PASS_REF, result);
     std::string file_path("/");
     file_path += kTestFilename;
     pp::FileRef file_ref(file_system, file_path.c_str());
     ASSERT_NE(0, file_ref.pp_resource());
 
+    // Ensure that the file can be queried.
+    TestCompletionCallbackWithOutput<PP_FileInfo> cc(instance_->pp_instance(),
+                                                     callback_type());
+    cc.WaitForResult(file_ref.Query(cc.GetCallback()));
+    CHECK_CALLBACK_BEHAVIOR(cc);
+    ASSERT_EQ(PP_OK, cc.result());
+
     // Read the file and test that its contents match.
     pp::FileIO file_io(instance_);
     ASSERT_NE(0, file_io.pp_resource());
     TestCompletionCallback callback(instance_->pp_instance(),
                                     callback_type());
     callback.WaitForResult(
         file_io.Open(file_ref, PP_FILEOPENFLAG_READ, callback.GetCallback()));
     CHECK_CALLBACK_BEHAVIOR(callback);
     ASSERT_EQ(PP_OK, callback.result());
 
@@ skipping 241 matching lines @@
     ASSERT_TRUE(received_value <= kThreadsToRun);
     ++received_counts[received_value];
   }
   ASSERT_EQ(received_counts, expected_counts);
 
   message_data_.clear();
   ASSERT_TRUE(ClearListeners());
 
   PASS();
 }