Remove unused exception types from WebCrypto. (Chromium-side)

BUG=441485

Review URL: https://codereview.chromium.org/795263002

Cr-Commit-Position: refs/heads/master@{#308169}

content/child/webcrypto/status.cc

@@ -204,7 +204,7 @@ Status Status::ErrorUnsupported(const std::string& message) {
 }
 
 Status Status::ErrorUnexpected() {
-  return Status(blink::WebCryptoErrorTypeUnknown,
+  return Status(blink::WebCryptoErrorTypeOperation,
                 "Something unexpected happened...");
 }
 

content/child/webcrypto/test/test_helpers.cc

@@ -80,15 +80,11 @@ static std::string ErrorTypeToString(blink::WebCryptoErrorType type) {
       return "SyntaxError";
     case blink::WebCryptoErrorTypeOperation:
       return "OperationError";
-    case blink::WebCryptoErrorTypeUnknown:
-      return "UnknownError";
-    case blink::WebCryptoErrorTypeInvalidState:
-      return "InvalidState";
     case blink::WebCryptoErrorTypeInvalidAccess:
       return "InvalidAccess";
+    default:
+      return "?";
   }
-
-  return "?";
 }
 
 std::string StatusToString(const Status& status) {