Send the value of google_brand::GetBrand in component update checks.

components/update_client/utils_unittest.cc

Index: components/update_client/utils_unittest.cc
diff --git a/components/update_client/utils_unittest.cc b/components/update_client/utils_unittest.cc
index 24539e2946b1b76fbf3161f474b0dd1ca2a90aa9..8153070573d006e861e6c87a84c78461caa58cac 100644
--- a/components/update_client/utils_unittest.cc
+++ b/components/update_client/utils_unittest.cc
@@ -57,4 +57,28 @@ TEST(UpdateClientUtils, VerifyFileHash256) {
           "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")));
 }
 
+// Tests that the brand matches ^([a-zA-Z]{4})?$
+TEST(UpdateClientUtils, IsValidBrand) {
+  EXPECT_TRUE(IsValidBrand(std::string("")));
+  EXPECT_TRUE(IsValidBrand(std::string("T")));
+  EXPECT_TRUE(IsValidBrand(std::string("TE")));
+  EXPECT_TRUE(IsValidBrand(std::string("TES")));
+  EXPECT_TRUE(IsValidBrand(std::string("TEST")));
+  EXPECT_TRUE(IsValidBrand(std::string("")));
+  EXPECT_TRUE(IsValidBrand(std::string("t")));
+  EXPECT_TRUE(IsValidBrand(std::string("te")));
+  EXPECT_TRUE(IsValidBrand(std::string("tes")));
+  EXPECT_TRUE(IsValidBrand(std::string("test")));
+  EXPECT_TRUE(IsValidBrand(std::string("TEst")));
+
+  EXPECT_FALSE(IsValidBrand(std::string("TESTS")));  // Too long.
+  EXPECT_FALSE(IsValidBrand(std::string("TES1")));   // Has digit.
+  EXPECT_FALSE(IsValidBrand(std::string(" TES")));   // Begins with white space.
+  EXPECT_FALSE(IsValidBrand(std::string("TES ")));   // Ends with white space.
+  EXPECT_FALSE(IsValidBrand(std::string("T ES")));   // Contains white space.
+  EXPECT_FALSE(IsValidBrand(std::string("<TE")));    // Has <.
+  EXPECT_FALSE(IsValidBrand(std::string("TE>")));    // Has >.
+  EXPECT_FALSE(IsValidBrand(std::string("\xaa")));   // Has non-ASCII char.
+}
+
 }  // namespace update_client