Improve Error Reporting

Adds more meaningful error reporting where possible to the DrmEngine.  Adds
translation of CDM and OEMCrypto errors to Android errors.

Bug: 8621516
Change-Id: Ibab8a8711c3929ed72870ec7e138cd42358d9fb3

libwvdrmengine/include/WVErrors.h

@@ -0,0 +1,23 @@
+//
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+
+#ifndef WV_ERRORS_H_
+#define WV_ERRORS_H_
+
+#include "media/stagefright/MediaErrors.h"
+
+namespace wvdrm {
+
+using android::ERROR_DRM_VENDOR_MIN;
+
+enum {
+  kErrorNeedProvisioning       = ERROR_DRM_VENDOR_MIN,
+  kErrorDeviceRevoked          = ERROR_DRM_VENDOR_MIN + 1,
+  kErrorIncorrectBufferSize    = ERROR_DRM_VENDOR_MIN + 2,
+  kErrorCDMGeneric             = ERROR_DRM_VENDOR_MIN + 3,
+};
+
+} // namespace wvdrm
+
+#endif // WV_ERRORS_H_