Change the WebCrypto behavior when importing EC private keys without a public key.

content/child/webcrypto/test/ecdsa_unittest.cc

Index: content/child/webcrypto/test/ecdsa_unittest.cc
diff --git a/content/child/webcrypto/test/ecdsa_unittest.cc b/content/child/webcrypto/test/ecdsa_unittest.cc
index 36e36ff438ed5b56950c3ab96600c68107e093b5..dc7707f9a2267050e04921a99c324246f732d749 100644
--- a/content/child/webcrypto/test/ecdsa_unittest.cc
+++ b/content/child/webcrypto/test/ecdsa_unittest.cc
@@ -346,9 +346,18 @@ TEST(WebCryptoEcdsaTest, ImportExportPrivateKey) {
     // Test from PKCS8, and then export to {JWK, PKCS8}
     // -------------------------------------------------
 
+    // The imported PKCS8 bytes may differ from the exported bytes (in the case
+    // where the publicKey was missing, it will be synthesized and written back
+    // during export).
+    std::vector<uint8_t> pkcs8_input_bytes;
+    if (test->HasKey("pkcs8_input"))
+      pkcs8_input_bytes = GetBytesFromHexString(test, "pkcs8_input");
+    CryptoData pkcs8_input_data(pkcs8_input_bytes.empty() ? pkcs8_bytes
+                                                          : pkcs8_input_bytes);
+
     // Import the key using PKCS8
     ASSERT_EQ(Status::Success(),
-              ImportKey(blink::WebCryptoKeyFormatPkcs8, CryptoData(pkcs8_bytes),
+              ImportKey(blink::WebCryptoKeyFormatPkcs8, pkcs8_input_data,
                         CreateEcdsaImportAlgorithm(curve), true,
                         blink::WebCryptoKeyUsageSign, &key));