Merge of CLs

* Move Properties::Init into platform-specific code

  This enables a refactor where property initialization for CE CDM will
  use values provided by the application during library initialization.

  [ Merge of http://go/wvgerrit/14510/ ]

* Add Properties::AlwaysUseKeySetIds().

  When true, all sessions will have key set IDs and all session IDs
  will be the same as the corresponding key set ID.

  This will help the new CDM interface stick more closely to the EME
  APIs, in which there are no such things as key set IDs and sessions
  only have a single, random ID used for both streaming and offline.

  [ Merge of http://go/wvgerrit/14521/ ]

* Reserve key set IDs in memory, rather than on the file system.

  This makes it more efficient to use key set IDs for non-offline
  sessions.

  [ Merge of http://go/wvgerrit/14535/ ]

Change-Id: I765c3519619b17cc3c4ef95b1a6b125f479ee1d0

libwvdrmengine/cdm/core/include/properties.h

@@ -54,6 +54,7 @@ class Properties {
                                      std::string* base_path);
   static bool GetFactoryKeyboxPath(std::string* keybox);
   static bool GetOEMCryptoPath(std::string* library_name);
+  static bool AlwaysUseKeySetIds();
   static bool GetSecurityLevelDirectories(std::vector<std::string>* dirs);
   static bool GetApplicationId(const CdmSessionId& session_id,
                                std::string* app_id);