[blimp] Change to use SHA-256 instead of SHA-1 for unique ids

blimp/common/blob_cache/id_util.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "blimp/common/blob_cache/id_util.h"
 
-#include "base/sha1.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "blimp/common/blob_cache/blob_cache.h"
+#include "crypto/sha2.h"
 
 namespace blimp {
 
 const BlobId CalculateBlobId(const void* data, size_t data_size) {
-  std::vector<unsigned char> sha1_hash(base::kSHA1Length);
-  base::SHA1HashBytes(static_cast<const unsigned char*>(data), data_size,
-                      sha1_hash.data());
-  return std::string(reinterpret_cast<char*>(sha1_hash.data()),
-                     sha1_hash.size());
+  return crypto::SHA256HashString(
+      base::StringPiece(reinterpret_cast<const char*>(data), data_size));
 }
 
-const std::string FormatBlobId(const BlobId& data) {
-  DCHECK_EQ(base::kSHA1Length, data.length());
-  return base::ToLowerASCII(base::HexEncode(data.data(), data.length()));
+const std::string FormatBlobId(const BlobId& id) {
+  DCHECK(BlobIdHasCorrectLength(id));
+  return base::ToLowerASCII(base::HexEncode(id.data(), id.length()));
+}
+
+bool BlobIdHasCorrectLength(const BlobId& id) {
+  return crypto::kSHA256Length == id.length();
 }
 
 }  // namespace blimp