Reject deriveBits() for PBKDF2 when given a length of 0.

components/webcrypto/status.h

Index: components/webcrypto/status.h
diff --git a/components/webcrypto/status.h b/components/webcrypto/status.h
index 2772e32d5b30e7626090f6690ca4b24344594176..73397d3f92a037541bce9f0cb14deb2df7ab8ffc 100644
--- a/components/webcrypto/status.h
+++ b/components/webcrypto/status.h
@@ -267,6 +267,9 @@ class Status {
   // No length parameter was provided for PBKDF2's Derive Bits operation.
   static Status ErrorPbkdf2DeriveBitsLengthNotSpecified();
 
+  // PBKDF2's deriveBits() was called with an unsupported length of 0.
+  static Status ErrorPbkdf2DeriveBitsLengthZero();
+
   // PBKDF2 was called with iterations == 0.
   static Status ErrorPbkdf2Iterations0();