Teach the GCM Driver how to decrypt incoming messages.

components/gcm_driver/crypto/encryption_header_parsers.cc

Index: components/gcm_driver/crypto/encryption_header_parsers.cc
diff --git a/components/gcm_driver/crypto/encryption_header_parsers.cc b/components/gcm_driver/crypto/encryption_header_parsers.cc
index 6a45792e85b04f480f1d095be40768f067306294..f320a101e69043554086d0d4c098085dad6b587a 100644
--- a/components/gcm_driver/crypto/encryption_header_parsers.cc
+++ b/components/gcm_driver/crypto/encryption_header_parsers.cc
@@ -56,24 +56,6 @@ bool ParseMultipleNameValueListsHeader(const std::string& input,
   return true;
 }
 
-// TODO(peter): Generalize a base64url implementation.
-// See https://tools.ietf.org/html/rfc4648#section-5
-bool Base64DecodeUrlSafe(const std::string& input, std::string* output) {
-  if (input.find_first_of("+/") != std::string::npos)
-    return false;
-
-  // Add padding.
-  size_t padded_size = (input.size() + 3) - (input.size() + 3) % 4;
-  std::string padded_input(input);
-  padded_input.resize(padded_size, '=');
-
-  // Convert to standard base64 alphabet.
-  base::ReplaceChars(padded_input, "-", "+", &padded_input);
-  base::ReplaceChars(padded_input, "_", "/", &padded_input);
-
-  return base::Base64Decode(padded_input, output);
-}
-
 // Parses the "salt" field of the Encryption header. Must be a base64url
 // encoded string that decodes to a string exactly 16 bytes in length.
 bool ParseSalt(const std::string& value, std::string* output) {
@@ -196,4 +178,22 @@ bool ParseEncryptionKeyHeader(const std::string& input,
   return true;
 }
 
+// TODO(peter): Generalize a base64url implementation.
+// See https://tools.ietf.org/html/rfc4648#section-5
+bool Base64DecodeUrlSafe(const std::string& input, std::string* output) {
+  if (input.find_first_of("+/") != std::string::npos)
+    return false;
+
+  // Add padding.
+  size_t padded_size = (input.size() + 3) - (input.size() + 3) % 4;
+  std::string padded_input(input);
+  padded_input.resize(padded_size, '=');
+
+  // Convert to standard base64 alphabet.
+  base::ReplaceChars(padded_input, "-", "+", &padded_input);
+  base::ReplaceChars(padded_input, "_", "/", &padded_input);
+
+  return base::Base64Decode(padded_input, output);
+}
+
 }  // namespace gcm