Add CdmFileIOProvider interface for use by cdm_adapter

media/cdm/cdm_adapter.h

Index: media/cdm/cdm_adapter.h
diff --git a/media/cdm/cdm_adapter.h b/media/cdm/cdm_adapter.h
index cb08f4a155d62ad63d7e75579be789c323f4e77d..392f5c3183e8eb6739b514c15a7bb27d7e6838f7 100644
--- a/media/cdm/cdm_adapter.h
+++ b/media/cdm/cdm_adapter.h
@@ -7,9 +7,11 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <string>
 #include <vector>
 
+#include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
@@ -32,8 +34,17 @@ namespace media {
 
 class AudioFramesImpl;
 class CdmAllocator;
+class CdmFileIO;
 class CdmWrapper;
 
+// Called when the CDM needs a FileIO object from the host to do file IO
+// operations. Returns NULL if a FileIO object cannot be obtained. Once a
+// valid FileIO object is returned, |client| must be valid until
+// FileIO::Close() is called. The CDM can call this method multiple times
+// to operate on different files.
+using CdmFileIOProviderCB =

[xhwang, 2016/04/18 21:09:22]

The naming is a bit odd since the callback does create a "Provider". 

Typically we call this a Create*CB, e.g. CreateCdmFileIOCB:

https://code.google.com/p/chromium/codesearch#search/&q=Create.*CB&sq=package...

[jrummell, 2016/04/19 23:59:29]

Done.

+    base::Callback<std::unique_ptr<CdmFileIO>(cdm::FileIOClient* client)>;
+
 class MEDIA_EXPORT CdmAdapter : public MediaKeys,
                                 public CdmContext,
                                 public Decryptor,
@@ -42,14 +53,16 @@ class MEDIA_EXPORT CdmAdapter : public MediaKeys,
  public:
   // Create the CDM using |cdm_path| and initialize it using |key_system| and
   // |cdm_config|. |allocator| is to be used whenever the CDM needs memory
-  // and to create VideoFrames. Callbacks will be used for events generated
-  // by the CDM. |cdm_created_cb| will be called when the CDM is loaded and
-  // initialized.
+  // and to create VideoFrames. |file_io_provider| is to be used whenever the
+  // CDM needs access to the file system. Callbacks will be used for events
+  // generated by the CDM. |cdm_created_cb| will be called when the CDM is
+  // loaded and initialized.
   static void Create(
       const std::string& key_system,
       const base::FilePath& cdm_path,
       const CdmConfig& cdm_config,
       scoped_ptr<CdmAllocator> allocator,
+      const CdmFileIOProviderCB& file_io_provider_cb,
       const SessionMessageCB& session_message_cb,
       const SessionClosedCB& session_closed_cb,
       const LegacySessionErrorCB& legacy_session_error_cb,
@@ -149,6 +162,7 @@ class MEDIA_EXPORT CdmAdapter : public MediaKeys,
   CdmAdapter(const std::string& key_system,
              const CdmConfig& cdm_config,
              scoped_ptr<CdmAllocator> allocator,
+             const CdmFileIOProviderCB& file_io_provider_cb,
              const SessionMessageCB& session_message_cb,
              const SessionClosedCB& session_closed_cb,
              const LegacySessionErrorCB& legacy_session_error_cb,
@@ -210,6 +224,7 @@ class MEDIA_EXPORT CdmAdapter : public MediaKeys,
   ChannelLayout audio_channel_layout_;
 
   scoped_ptr<CdmAllocator> allocator_;
+  CdmFileIOProviderCB file_io_provider_cb_;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;