Use Inheritence for OEMCrypto Mock Properties

Merge from Widevine repo of http://go/wvgerrit/24728

We use compiler options to set different properties in the oemcrypto
mock.  With this CL, we define a base class that has default
properties.  All other variants need only define the properties that
they change.

b/35141278
b/37353534

Change-Id: Id38ec5bf35dcd83cea9a066ebe201e6da7c1a2b0

libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.h

@@ -28,10 +28,14 @@ typedef std::map<SessionId, SessionContext*> ActiveSessions;
 
 class CryptoEngine {
  public:
-  CryptoEngine(wvcdm::FileSystem* file_system);
-  ~CryptoEngine();
+  // This is like a factory method, except we choose which version to use at
+  // compile time.  It is defined in several source files.  The build system
+  // should choose which one to use by only linking in the correct one.
+  static CryptoEngine* MakeCryptoEngine(wvcdm::FileSystem* file_system);
 
-  bool Initialized() { return true; }
+  virtual ~CryptoEngine();
+
+  virtual bool Initialize() { return true; }
 
   bool ValidRootOfTrust() { return root_of_trust_.Validate(); }
 
@@ -59,7 +63,7 @@ class CryptoEngine {
     return root_of_trust_.DeviceToken();
   }
 
-  void Terminate();
+  virtual void Terminate() {}
 
   SessionId CreateSession();
 
@@ -75,24 +79,60 @@ class CryptoEngine {
     return kMaxSupportedOEMCryptoSessions;
   }
 
-  // Configuration constants - controls behavior of this CryptoEngine
-  OEMCrypto_HDCP_Capability config_current_hdcp_capability();
-  OEMCrypto_HDCP_Capability config_maximum_hdcp_capability();
+  // Returns the HDCP version currently in use.
+  virtual OEMCrypto_HDCP_Capability config_current_hdcp_capability();
+
+  // Returns the max HDCP version supported.
+  virtual OEMCrypto_HDCP_Capability config_maximum_hdcp_capability();
 
   UsageTable& usage_table() { return usage_table_; }
   wvcdm::FileSystem* file_system() { return file_system_; }
 
-  bool config_local_display_only();
-  bool config_closed_platform();
-  bool config_supports_usage_table();
-  bool config_supports_keybox();
-  OEMCrypto_ProvisioningMethod config_provisioning_method();
-  OEMCryptoResult get_oem_certificate(SessionContext* session,
-                                      uint8_t* public_cert,
-                                      size_t* public_cert_length);
-  bool config_is_anti_rollback_hw_present();
-  const char* config_security_level();
-  uint8_t config_security_patch_level();
+  // If config_local_display_only() returns true, we pretend we are using a
+  // built-in display, instead of HDMI or WiFi output.
+  virtual bool config_local_display_only() { return false; }
+
+  // A closed platform is permitted to use clear buffers.
+  virtual bool config_closed_platform() { return false; }
+
+  // Returns true if the client supports persistent storage of
+  // offline usage table information.
+  virtual bool config_supports_usage_table() { return true; }
+
+  virtual OEMCrypto_ProvisioningMethod config_provisioning_method() {
+    return OEMCrypto_Keybox;
+  }
+
+  virtual OEMCryptoResult get_oem_certificate(SessionContext* session,
+                                              uint8_t* public_cert,
+                                              size_t* public_cert_length) {
+    return OEMCrypto_ERROR_NOT_IMPLEMENTED;
+  }
+
+  // Used for OEMCrypto_IsAntiRollbackHwPresent.
+  virtual bool config_is_anti_rollback_hw_present() { return false; }
+
+  // Returns "L3" for a software only library.  L1 is for hardware protected
+  // data paths.
+  virtual const char* config_security_level() { return "L3"; }
+
+  // This should start at 0, and be incremented only when a security patch has
+  // been applied to the device that fixes a security bug.
+  virtual uint8_t config_security_patch_level() { return 0; }
+
+  // If 0 no restriction, otherwise it's the max buffer for DecryptCENC.
+  virtual size_t max_buffer_size() { return 1024 * 100; }  // 100 KiB.
+
+  // Set destination pointer based on the output destination description.
+  OEMCryptoResult SetDestination(OEMCrypto_DestBufferDesc* out_description,
+                                 size_t data_length, uint8_t subsample_flags);
+
+  // The current destination.
+  uint8_t* destination() { return destination_; }
+
+ protected:
+  explicit CryptoEngine(wvcdm::FileSystem* file_system);
+  uint8_t* destination_;
 
  private:
   ActiveSessions sessions_;