Support Per-Origin Provisioning

This is a merge of several Widevine-side commits that, cumulatively,
allow callers to specify an origin to be used to isolate data storage
as specified in the W3C Encrypted Media Extension specification.
Separate origins have separate certificates, and consequently cannot
share device identifiers with each other.

The changes included in this are:

Add Ability to Check for Existing Certificates
    http://go/wvgerrit/13974
Add Ability to Remove the Certificate
    http://go/wvgerrit/13975
Make CDM Origin-Aware
    http://go/wvgerrit/13977
Add Per-Origin Storage to Widevine CDM on Android
    http://go/wvgerrit/14026
Remove Automatic Origin Generation
    http://go/wvgerrit/14031

Bug: 19771858
Change-Id: I6a01c705d9b6b4887a9c7e6ff4399a125f781569

libwvdrmengine/cdm/include/wv_content_decryption_module.h

@@ -28,6 +28,7 @@ class WvContentDecryptionModule : public TimerHandler {
   // Session related methods
   virtual CdmResponseType OpenSession(const CdmKeySystem& key_system,
                                       CdmClientPropertySet* property_set,
+                                      const std::string& origin,
                                       WvCdmEventListener* event_listener,
                                       CdmSessionId* session_id);
   virtual CdmResponseType CloseSession(const CdmSessionId& session_id);
@@ -40,6 +41,7 @@ class WvContentDecryptionModule : public TimerHandler {
                                              const CdmLicenseType license_type,
                                              CdmAppParameterMap& app_parameters,
                                              CdmClientPropertySet* property_set,
+                                             const std::string& origin,
                                              CdmKeyMessage* key_request,
                                              CdmKeyRequestType* key_request_type,
                                              std::string* server_url);
@@ -75,15 +77,18 @@ class WvContentDecryptionModule : public TimerHandler {
   virtual CdmResponseType GetProvisioningRequest(
       CdmCertificateType cert_type,
       const std::string& cert_authority,
+      const std::string& origin,
       CdmProvisioningRequest* request,
       std::string* default_url);
 
   virtual CdmResponseType HandleProvisioningResponse(
+      const std::string& origin,
       CdmProvisioningResponse& response,
       std::string* cert,
       std::string* wrapped_key);
 
-  virtual CdmResponseType Unprovision(CdmSecurityLevel level);
+  virtual CdmResponseType Unprovision(CdmSecurityLevel level,
+                                      const std::string& origin);
 
   // Secure stop related methods
   virtual CdmResponseType GetUsageInfo(const std::string& app_id,