Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc

 // Copyright (c) 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 "components/user_prefs/tracked/registry_hash_store_contents_win.h"
 
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_reg_util_win.h"
 #include "base/values.h"
 #include "base/win/registry.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 constexpr base::char16 kProfileName[] = L"test_profile";
 constexpr base::char16 kStoreKeyName[] = L"Foo\\TestStore";
 
-// MACs are 32 characters long.
-constexpr char kTestStringA[] = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
-constexpr char kTestStringB[] = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
+// MACs are 32 characters long, which stored in the registry are 64 characters
+// long due to 8-bit to 16-bit char conversion.

[gab, 2016/08/08 04:37:46]

Hmmmm? UTF8ToUTF16 shouldn't change the size of the string?

[proberge, 2016/08/31 17:30:17]

I asked @grt why he used REG_BINARY instead of REG_SZ when writing to the
registry in platform_state_store_win.cc.

He replied: "storing a std::string in the registry as REG_SZ will 2x the space
used due to the 8-bit to 16-bit char conversion"

Should I use REG_BINARY instead to save on registry space?

+constexpr char kTestStringA[] =
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
+constexpr char kTestStringB[] =
+    "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
 
 constexpr char kAtomicPrefPath[] = "path1";
 constexpr char kSplitPrefPath[] = "extension";
 
 class RegistryHashStoreContentsWinTest : public testing::Test {
  protected:
   RegistryHashStoreContentsWinTest() {}
 
   void SetUp() override {
     registry_override_manager_.OverrideRegistry(HKEY_CURRENT_USER);
@@ skipping 76 matching lines @@
 
   contents->Reset();
 
   stored_mac.clear();
   EXPECT_FALSE(contents->GetMac(kAtomicPrefPath, &stored_mac));
   EXPECT_TRUE(stored_mac.empty());
 
   split_macs.clear();
   EXPECT_FALSE(contents->GetSplitMacs(kSplitPrefPath, &split_macs));
   EXPECT_EQ(0U, split_macs.size());
-}
+}