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

BUG=534964

Review-Url: https://codereview.chromium.org/2164753002
Cr-Commit-Position: refs/heads/master@{#406393}
diff --git a/components/webcrypto/status.cc b/components/webcrypto/status.cc
index 4747a7f0..f0d25ff4 100644
--- a/components/webcrypto/status.cc
+++ b/components/webcrypto/status.cc
@@ -351,6 +351,12 @@
       "No length was specified for the PBKDF2 Derive Bits operation.");
 }
 
+Status Status::ErrorPbkdf2DeriveBitsLengthZero() {
+  return Status(
+      blink::WebCryptoErrorTypeOperation,
+      "A length of 0 was specified for PBKDF2's Derive Bits operation.");
+}
+
 Status Status::ErrorPbkdf2Iterations0() {
   return Status(blink::WebCryptoErrorTypeOperation,
                 "PBKDF2 requires iterations > 0");