rewrite_to_chrome_style: Avoid asserts when checking for const-ness.

Just skip expressions that are dependent on template parameters, treat
them as non-constant.

R=dcheng
BUG=581218

Review URL: https://codereview.chromium.org/1645243002

Cr-Commit-Position: refs/heads/master@{#372256}

tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp

@@ -157,6 +157,15 @@ bool IsProbablyConst(const clang::VarDecl& decl,
   if (!initializer)
     return false;
 
+  // If the expression is dependent on a template input, then we are not
+  // sure if it can be compile-time generated as calling isEvaluatable() is
+  // not valid on |initializer|.
+  // TODO(crbug.com/581218): We could probably look at each compiled
+  // instantiation of the template and see if they are all compile-time
+  // isEvaluable().
+  if (initializer->isInstantiationDependent())
+    return false;
+
   // If the expression can be evaluated at compile time, then it should have a
   // kFoo style name. Otherwise, not.
   return initializer->isEvaluatable(context);

tools/clang/rewrite_to_chrome_style/tests/template-expected.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+namespace blink {
+
+template <typename T, int number>
+void F() {
+  // We don't assert on this, and we don't end up considering it a const for
+  // now.
+  const int maybe_a_const = sizeof(T);
+  const int is_a_const = number;
+}
+
+template <int number, typename... T>
+void F() {
+  // We don't assert on this, and we don't end up considering it a const for
+  // now.
+  const int maybe_a_const = sizeof...(T);
+  const int is_a_const = number;
+}
+
+}  // namespace blink

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

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+namespace blink {
+
+template <typename T, int number>
+void F() {
+  // We don't assert on this, and we don't end up considering it a const for
+  // now.
+  const int maybe_a_const = sizeof(T);
+  const int is_a_const = number;
+}
+
+template <int number, typename... T>
+void F() {
+  // We don't assert on this, and we don't end up considering it a const for
+  // now.
+  const int maybe_a_const = sizeof...(T);
+  const int is_a_const = number;
+}
+
+}  // namespace blink