Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc

Index: components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc
diff --git a/components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc b/components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc
index 411c0b19e4ac08fd6f5d10aab352e6b777dd46d6..fc9ee8ed62840073234166b5c64f086b754cb78f 100644
--- a/components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc
+++ b/components/user_prefs/tracked/registry_hash_store_contents_win_unittest.cc
@@ -16,9 +16,12 @@ 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";
@@ -115,4 +118,4 @@ TEST_F(RegistryHashStoreContentsWinTest, TestReset) {
   split_macs.clear();
   EXPECT_FALSE(contents->GetSplitMacs(kSplitPrefPath, &split_macs));
   EXPECT_EQ(0U, split_macs.size());
-}
+}