Reland of place string::find(prefix) == 0 pattern with base::StartsWith().

components/os_crypt/os_crypt_posix.cc

Index: components/os_crypt/os_crypt_posix.cc
diff --git a/components/os_crypt/os_crypt_posix.cc b/components/os_crypt/os_crypt_posix.cc
index 44f04b3801fead7d45d2758260c9721db6bf9334..24a411e9bd6b1461e4f942f0723ed97b8eaa22e3 100644
--- a/components/os_crypt/os_crypt_posix.cc
+++ b/components/os_crypt/os_crypt_posix.cc
@@ -9,6 +9,7 @@
 #include <memory>
 
 #include "base/logging.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "crypto/encryptor.h"
 #include "crypto/symmetric_key.h"
@@ -118,7 +119,8 @@
   // old data saved as clear text and we'll return it directly.
   // Credit card numbers are current legacy data, so false match with prefix
   // won't happen.
-  if (ciphertext.find(kObfuscationPrefix) != 0) {
+  if (!base::StartsWith(ciphertext, kObfuscationPrefix,
+                        base::CompareCase::SENSITIVE)) {
     *plaintext = ciphertext;
     return true;
   }