Add PolicyEngine::SetLicenseForRelease()

* Add CE test for incomplete remove()

  [ Merge of http://go/wvgerrit/14658 ]

  This depends on I064c053dd986a432865163aed5c9c3493f14340b to get
  PolicyEngine to implement the EME semantics expressed in this test.

  This also excludes another error code from causing an error log in
  CdmEngine::AddKey, because this is actually an expected, handled
  error in the CE CDM and it causes some confusing noise during testing
  and development.

* Drop CdmEngine test main

  [ Merge of http://go/wvgerrit/14693 ]

  The command-line arguments are no longer in use anywhere, and
  dropping the CdmEngine test's main allows me to add those tests to
  the CE test suite.

* Add PolicyEngine::SetLicenseForRelease()

  [ Merge of http://go/wvgerrit/14651 ]

  In order to implement the EME-specified behaviors for load() &
  remove(), some small changes are required in PolicyEngine.

  According to EME, you should be able to remove() an active session.
  This means that releasing a persistent session is not a separate load
  operation.  EME also states that the keys should be expired when this
  is done.

  Remove() is implemented using GenerateKeyRequest(type=release).  This
  leads to CdmLicense::RestoreLicenseForRelease, which in turn calls
  PolicyEngine::SetLicense.  When removing an active session, the policy
  engine will have keys already loaded.  The old behavior would cause
  these keys to be reloaded.  We need them to be expired, instead.

  Once a remove() has been started, the keys should never be loadable
  again.  If a release confirmation is not received by the CDM, the
  session should still be loadable.  EME states that once a session has
  had remove() called, then is loaded again later, there should be no
  keys.  Not that they should be expired, but not present.  The old
  behavior would cause these keys to be reloaded as usable.

  This new method allows EME remove() and load() behaviors to be
  faithfully implemented in the CE CDM.  When removing an active
  session, the old keys become expired.  When removing a partially-
  removed, newly-loaded session, no keys will be loaded at all.

  This change does not affect any existing tests in core/.

  New tests have been added in PolicyEngineTest to cover the behavior
  of the new method.

Change-Id: Idd61487c277c9eadb4a044cb2a563e151442a548

libwvdrmengine/cdm/core/test/url_request.cpp

@@ -109,7 +109,7 @@ bool UrlRequest::GetResponse(std::string* message) {
   }
 
   ConcatenateChunkedResponse(response, message);
-  LOGD("HTTP response: (%d): %s", message->size(), b2a_hex(*message).c_str());
+  LOGV("HTTP response: (%d): %s", message->size(), b2a_hex(*message).c_str());
   return true;
 }
 
@@ -154,7 +154,7 @@ bool UrlRequest::PostRequestWithPath(const std::string& path,
   request.append(data);
 
   int ret = socket_.Write(request.c_str(), request.size(), kWriteTimeoutMs);
-  LOGD("HTTP request: (%d): %s", request.size(), b2a_hex(request).c_str());
+  LOGV("HTTP request: (%d): %s", request.size(), b2a_hex(request).c_str());
   return ret != -1;
 }