rewrite_to_chrome_style: Check expression is const when deciding style

tools/clang/rewrite_to_chrome_style/tests/constants-original.cc

Index: tools/clang/rewrite_to_chrome_style/tests/constants-original.cc
diff --git a/tools/clang/rewrite_to_chrome_style/tests/constants-original.cc b/tools/clang/rewrite_to_chrome_style/tests/constants-original.cc
index e9e211260bd3ed6235bf67bee8db94e2c7b60984..96d974de77c17c011c785ee7a6f7813e20950ebe 100644
--- a/tools/clang/rewrite_to_chrome_style/tests/constants-original.cc
+++ b/tools/clang/rewrite_to_chrome_style/tests/constants-original.cc
@@ -25,6 +25,19 @@ class C {
 
   // Not a constant even though it has static storage duration.
   static const char* m_currentEvent;
+
+  static int Function();
+
+  static void FunctionWithConstant() {
+    const int kFunctionConstant = 4;
+    const int kFunctionConstantFromExpression = 4 + 6;
+    const int kFunctionConstantFromOtherConsts =
+        kFunctionConstant + kFunctionConstantFromExpression;
+    const int should_be_renamed_to_a_const = 9 - 2;
+    const int should_also_be_renamed_to_a_const =
+        kFunctionConstant + kFunctionConstantFromOtherConsts;
+    const int not_compile_time_const = kFunctionConstant + Function();
+  }
 };
 
 void F() {