Add CdmFileIOProvider interface for use by cdm_adapter

media/cdm/aes_decryptor_unittest.cc

Index: media/cdm/aes_decryptor_unittest.cc
diff --git a/media/cdm/aes_decryptor_unittest.cc b/media/cdm/aes_decryptor_unittest.cc
index 47ed0ab57cd4e45a9b6fc3a4baebee5e4384b32c..2d1b8e0eb0d31e9478ef85f6b626eff23e3fbec7 100644
--- a/media/cdm/aes_decryptor_unittest.cc
+++ b/media/cdm/aes_decryptor_unittest.cc
@@ -24,6 +24,7 @@
 #include "media/cdm/cdm_adapter.h"
 #include "media/cdm/external_clear_key_test_helper.h"
 #include "media/cdm/simple_cdm_allocator.h"
+#include "media/cdm/simple_cdm_file_io_provider.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest-param-test.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -246,10 +247,12 @@ class AesDecryptorTest : public testing::TestWithParam<std::string> {
 
       helper_.reset(new ExternalClearKeyTestHelper());
       scoped_ptr<CdmAllocator> allocator(new SimpleCdmAllocator());
+      scoped_ptr<CdmFileIOProvider> provider(new SimpleCdmFileIOProvider());
       CdmAdapter::Create(
           helper_->KeySystemName(), helper_->LibraryPath(), cdm_config,
-          std::move(allocator), base::Bind(&AesDecryptorTest::OnSessionMessage,
-                                           base::Unretained(this)),
+          std::move(allocator), std::move(provider),
+          base::Bind(&AesDecryptorTest::OnSessionMessage,
+                     base::Unretained(this)),
           base::Bind(&AesDecryptorTest::OnSessionClosed,
                      base::Unretained(this)),
           base::Bind(&AesDecryptorTest::OnLegacySessionError,