Fix SetupUtilTest.StoreDMTokenToRegistry.

To create a "binary" std::string with embedded nulls from a C string,
use the 2 argument constructor so that std::string does not use embedded
nulls to determine the full length of the string.

Bug: None
Change-Id: I6003984b6179d03753fef402134329523fe4c31a
Reviewed-on: https://chromium-review.googlesource.com/973692
Commit-Queue: Roger Tawa <rogerta@chromium.org>
Reviewed-by: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545123}

chrome/installer/setup/setup_util_unittest.cc

@@ -476,7 +476,12 @@ TEST(SetupUtilTest, StoreDMTokenToRegistry) {
   registry_util::RegistryOverrideManager registry_override_manager;
   registry_override_manager.OverrideRegistry(HKEY_LOCAL_MACHINE);
 
-  std::string token("tokens are \0 binary data");
+  // Use the 2 argument std::string constructor so that the length of the string
+  // is not calculated by assuming the input char array is null terminated.
+  static constexpr char kTokenData[] = "tokens are \0 binary data";
+  static constexpr DWORD kExpectedSize = sizeof(kTokenData) - 1;
+  std::string token(&kTokenData[0], kExpectedSize);
+  ASSERT_EQ(kExpectedSize, token.length());
   EXPECT_TRUE(installer::StoreDMToken(token));
 
   std::wstring path;
@@ -486,14 +491,14 @@ TEST(SetupUtilTest, StoreDMTokenToRegistry) {
   ASSERT_EQ(ERROR_SUCCESS, key.Open(HKEY_LOCAL_MACHINE, path.c_str(),
                                     KEY_QUERY_VALUE | KEY_WOW64_64KEY));
 
-  DWORD size = 64;
+  DWORD size = kExpectedSize;
   std::vector<char> raw_value(size);
   DWORD dtype;
   ASSERT_EQ(ERROR_SUCCESS,
             key.ReadValue(name.c_str(), raw_value.data(), &size, &dtype));
   EXPECT_EQ(REG_BINARY, dtype);
-  ASSERT_EQ(token.length(), size);
-  EXPECT_EQ(0, memcmp(token.data(), raw_value.data(), size));
+  ASSERT_EQ(kExpectedSize, size);
+  EXPECT_EQ(0, memcmp(token.data(), raw_value.data(), kExpectedSize));
 }
 
 namespace installer {