diff --git a/dom/media/gmp/GMPDecryptorParent.cpp b/dom/media/gmp/GMPDecryptorParent.cpp
index d9e25d952f05..aa286c7b0398 100644
--- a/dom/media/gmp/GMPDecryptorParent.cpp
+++ b/dom/media/gmp/GMPDecryptorParent.cpp
@@ -245,6 +245,7 @@ GMPExToNsresult(GMPDOMException aDomException) {
     case kGMPAbortError: return NS_ERROR_DOM_ABORT_ERR;
     case kGMPQuotaExceededError: return NS_ERROR_DOM_QUOTA_EXCEEDED_ERR;
     case kGMPTimeoutError: return NS_ERROR_DOM_TIMEOUT_ERR;
+    case kGMPTypeError: return NS_ERROR_DOM_TYPE_ERR;
     default: return NS_ERROR_DOM_UNKNOWN_ERR;
   }
 }
diff --git a/dom/media/gmp/GMPMessageUtils.h b/dom/media/gmp/GMPMessageUtils.h
index ad4e90313256..13f6127f3a22 100644
--- a/dom/media/gmp/GMPMessageUtils.h
+++ b/dom/media/gmp/GMPMessageUtils.h
@@ -34,6 +34,7 @@ struct GMPDomExceptionValidator {
       case kGMPAbortError:
       case kGMPQuotaExceededError:
       case kGMPTimeoutError:
+      case kGMPTypeError:
         return true;
       default:
         return false;
diff --git a/dom/media/gmp/gmp-api/gmp-decryption.h b/dom/media/gmp/gmp-api/gmp-decryption.h
index f8e2b9928ead..046a05759eb5 100644
--- a/dom/media/gmp/gmp-api/gmp-decryption.h
+++ b/dom/media/gmp/gmp-api/gmp-decryption.h
@@ -79,7 +79,8 @@ enum GMPDOMException {
   kGMPSecurityError = 18,
   kGMPAbortError = 20,
   kGMPQuotaExceededError = 22,
-  kGMPTimeoutError = 23
+  kGMPTimeoutError = 23,
+  kGMPTypeError = 52
 };
 
 enum GMPSessionMessageType {
diff --git a/dom/media/gmp/widevine-adapter/WidevineDecryptor.cpp b/dom/media/gmp/widevine-adapter/WidevineDecryptor.cpp
index b9220b8d50fe..1c43ba43a987 100644
--- a/dom/media/gmp/widevine-adapter/WidevineDecryptor.cpp
+++ b/dom/media/gmp/widevine-adapter/WidevineDecryptor.cpp
@@ -321,7 +321,12 @@ ToGMPDOMException(cdm::Error aError)
   switch (aError) {
     case kNotSupportedError: return kGMPNotSupportedError;
     case kInvalidStateError: return kGMPInvalidStateError;
-    case kInvalidAccessError: return kGMPInvalidAccessError;
+    case kInvalidAccessError:
+      // Note: Chrome converts kInvalidAccessError to TypeError, since the
+      // Chromium CDM API doesn't have a type error enum value. The EME spec
+      // requires TypeError in some places, so we do the same conversion.
+      // See bug 1313202.
+      return kGMPTypeError;
     case kQuotaExceededError: return kGMPQuotaExceededError;
     case kUnknownError: return kGMPInvalidModificationError; // Note: Unique placeholder.
     case kClientError: return kGMPAbortError; // Note: Unique placeholder.