Refactor: Extract some duplicated code for verifying usages during import of asymmetric key.

content/child/webcrypto/webcrypto_util.h

Index: content/child/webcrypto/webcrypto_util.h
diff --git a/content/child/webcrypto/webcrypto_util.h b/content/child/webcrypto/webcrypto_util.h
index fdfea99316d02933d3d9f503f25b09f6beb630a6..8b8e2195e2e677796e682a454a51db85231c75ba 100644
--- a/content/child/webcrypto/webcrypto_util.h
+++ b/content/child/webcrypto/webcrypto_util.h
@@ -81,6 +81,13 @@ Status GetRsaKeyGenParameters(
     unsigned int* public_exponent,
     unsigned int* modulus_length_bits);
 
+// Verifies that |usages| is valid when importing a key of the given format.
+Status VerifyUsagesBeforeImportAsymmetricKey(
+    blink::WebCryptoKeyFormat format,
+    blink::WebCryptoKeyUsageMask all_public_key_usages,
+    blink::WebCryptoKeyUsageMask all_private_key_usages,
+    blink::WebCryptoKeyUsageMask usages);
+
 }  // namespace webcrypto
 
 }  // namespace content