Add allocator interface for use by cdm_adapter

media/cdm/cdm_adapter_unittest.cc

Index: media/cdm/cdm_adapter_unittest.cc
diff --git a/media/cdm/cdm_adapter_unittest.cc b/media/cdm/cdm_adapter_unittest.cc
index 46de9244e02e10beba5691d440a71156232d0006..95787f32b8e215191984fdf26f85c28a1fc9937b 100644
--- a/media/cdm/cdm_adapter_unittest.cc
+++ b/media/cdm/cdm_adapter_unittest.cc
@@ -13,6 +13,7 @@
 #include "media/base/cdm_key_information.h"
 #include "media/base/media_keys.h"
 #include "media/cdm/cdm_adapter.h"
+#include "media/cdm/cdm_buffer_allocator_impl.h"
 #include "media/cdm/external_clear_key_test_helper.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -92,7 +93,8 @@ class CdmAdapterTest : public testing::Test {
         base::Bind(&CdmAdapterTest::OnSessionExpirationUpdate,
                    base::Unretained(this)),
         base::Bind(&CdmAdapterTest::OnCdmCreated, base::Unretained(this),
-                   expected_result));
+                   expected_result),
+        new CdmBufferAllocatorImpl());
     RunUntilIdle();
   }