Add decrypt hash support

[ Merge of http://go/wvgerrit/68083 ]

Add ability to query decrypt hash support, set a hash computed over a frame
and retrieve the last error at a later point.

Bug: 34080802
Test: WV unit/integration tests. New tests added to cdm_engine_test,
      libwvdrmdrmplugin_hidl_test and request_license_test.

Change-Id: I7548c8798c873a6af3e1cfc0df57c117e1e474a6

libwvdrmengine/mediadrm/include/WVDrmPlugin.h

@@ -263,6 +263,8 @@ class WVDrmPlugin : public android::DrmPlugin,
 
   std::string mProvisioningServiceCertificate;
 
+  CdmSessionId mDecryptHashSessionId;
+
   status_t queryProperty(const std::string& property,
                          std::string& stringValue) const;