media: Add UMA to report CDM interface version being used

media/cdm/cdm_wrapper.h

 // Copyright 2013 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.
 
 #ifndef MEDIA_CDM_CDM_WRAPPER_H_
 #define MEDIA_CDM_CDM_WRAPPER_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 40 matching lines @@
 // Since this file is highly templated and default implementations are short
 // (just a shim layer in most cases), everything is done in this header file.
 class CdmWrapper {
  public:
   static CdmWrapper* Create(CreateCdmFunc create_cdm_func,
                             const char* key_system,
                             uint32_t key_system_size,
                             GetCdmHostFunc get_cdm_host_func,
                             void* user_data);
 
-  virtual ~CdmWrapper(){};
+  virtual ~CdmWrapper() {}
+
+  // Returns the version of the CDM interface that the created CDM uses.
+  virtual int GetVersion() = 0;

[ddorwin, 2016/08/22 20:38:15]

Get*API*Version or something like that.
(In theory, the Host and CDM APIs could diverge, but I guess we don't need to
worry about that.)

Also, update the CL description.

[xhwang, 2016/08/23 00:21:43]

Done.

 
   virtual void Initialize(bool allow_distinctive_identifier,
                           bool allow_persistent_state) = 0;
   virtual void SetServerCertificate(uint32_t promise_id,
                                     const uint8_t* server_certificate_data,
                                     uint32_t server_certificate_data_size) = 0;
   virtual void CreateSessionAndGenerateRequest(uint32_t promise_id,
                                                cdm::SessionType session_type,
                                                cdm::InitDataType init_data_type,
                                                const uint8_t* init_data,
@@ skipping 58 matching lines @@
                         get_cdm_host_func, user_data);
     if (!cdm_instance)
       return nullptr;
 
     return new CdmWrapperImpl<CdmInterface>(
         static_cast<CdmInterface*>(cdm_instance));
   }
 
   ~CdmWrapperImpl() override { cdm_->Destroy(); }
 
+  int GetVersion() override { return CdmInterface::kVersion; }
+
   void Initialize(bool allow_distinctive_identifier,
                   bool allow_persistent_state) override {
     cdm_->Initialize(allow_distinctive_identifier, allow_persistent_state);
   }
 
   void SetServerCertificate(uint32_t promise_id,
                             const uint8_t* server_certificate_data,
                             uint32_t server_certificate_data_size) override {
     cdm_->SetServerCertificate(promise_id, server_certificate_data,
                                server_certificate_data_size);
@@ skipping 169 matching lines @@
 // Also update supported_cdm_versions.h.
 static_assert(cdm::ContentDecryptionModule::kVersion ==
                   cdm::ContentDecryptionModule_8::kVersion,
               "ensure cdm wrapper templates have old version support");
 
 }  // namespace media
 
 #undef PLATFORM_DCHECK
 
 #endif  // MEDIA_CDM_CDM_WRAPPER_H_