Extract Extension IME related utility.

chrome/browser/chromeos/input_method/input_method_util_unittest.cc

Index: chrome/browser/chromeos/input_method/input_method_util_unittest.cc
diff --git a/chrome/browser/chromeos/input_method/input_method_util_unittest.cc b/chrome/browser/chromeos/input_method/input_method_util_unittest.cc
index edeaafbb4c4d1f6d0323bb2449b0b4dc7063ded1..204ff913f6ba5e946fded7012f6452d46906f318 100644
--- a/chrome/browser/chromeos/input_method/input_method_util_unittest.cc
+++ b/chrome/browser/chromeos/input_method/input_method_util_unittest.cc
@@ -307,13 +307,6 @@ TEST_F(InputMethodUtilTest, TestIsKeyboardLayout) {
   EXPECT_FALSE(InputMethodUtil::IsKeyboardLayout("mozc"));
 }
 
-TEST_F(InputMethodUtilTest, TestExtensionInputMethod) {
-  EXPECT_TRUE(InputMethodUtil::IsExtensionInputMethod(
-      kExtensionImePrefix + std::string("123abc")));
-  EXPECT_FALSE(InputMethodUtil::IsExtensionInputMethod(""));
-  EXPECT_FALSE(InputMethodUtil::IsExtensionInputMethod("mozc"));
-}
-
 TEST_F(InputMethodUtilTest, TestGetKeyboardLayoutName) {
   // Unsupported case.
   EXPECT_EQ("", util_.GetKeyboardLayoutName("UNSUPPORTED_ID"));