Infrastructure changes to support big usage tables

[ Merge of http://go/wvgerrit/23161 ]

The usage table redesign will require storing usage table headers
and usage entries in non-secure persistent store. This information
will be signed by the TEE to prevent against modification. New
Storage and retrieval methods have been added for usage table headers,
while usage entries will be stored alongside (offline) licenses and
(secure stops/)usage info.

b/34327459

Test: All unittests, including newly introduced ones other than some
oemcrypto, request_license_test passed. Those tests failed with or without
this CL.

Change-Id: I9b8d6210e33774b0803f8af1711b2d593d467aec

libwvdrmengine/cdm/core/src/cdm_engine.cpp

@@ -854,8 +854,9 @@ CdmResponseType CdmEngine::GetUsageInfo(const std::string& app_id,
 
   CdmKeyMessage license_request;
   CdmKeyResponse license_response;
+  std::string usage_entry;
   if (!handle.RetrieveUsageInfo(app_id, ssid, &license_request,
-                                &license_response)) {
+                                &license_response, &usage_entry)) {
     usage_property_set_->set_security_level(kLevel3);
     usage_property_set_->set_app_id(app_id);
     usage_session_.reset(new CdmSession(file_system_));
@@ -869,7 +870,7 @@ CdmResponseType CdmEngine::GetUsageInfo(const std::string& app_id,
       return GET_USAGE_INFO_ERROR_2;
     }
     if (!handle.RetrieveUsageInfo(app_id, ssid, &license_request,
-                                  &license_response)) {
+                                  &license_response, &usage_entry)) {
       // No entry found for that ssid.
       return USAGE_INFO_NOT_FOUND;
     }
@@ -1084,8 +1085,9 @@ CdmResponseType CdmEngine::LoadUsageSession(const CdmKeySetId& key_set_id,
 
   CdmKeyMessage key_message;
   CdmKeyResponse key_response;
+  std::string usage_entry;
   if (!handle.RetrieveUsageInfoByKeySetId(app_id, key_set_id, &key_message,
-                                          &key_response)) {
+                                          &key_response, &usage_entry)) {
     LOGE("CdmEngine::LoadUsageSession: unable to find usage information");
     return LOAD_USAGE_INFO_MISSING;
   }