Remove deprecated ListValue::Append(Value*) overload on Linux.

base/values.h

Index: base/values.h
diff --git a/base/values.h b/base/values.h
index 32441ae73fbc0b0f1448bb7a89be4eebb52d6ed1..43d400c659924b1e52f4eb5bb420169aa3297aa5 100644
--- a/base/values.h
+++ b/base/values.h
@@ -457,8 +457,10 @@ class BASE_EXPORT ListValue : public Value {
 
   // Appends a Value to the end of the list.
   void Append(std::unique_ptr<Value> in_value);
+#if !defined(OS_LINUX) || defined(OS_CHROMEOS)
   // Deprecated version of the above. TODO(estade): remove.
   void Append(Value* in_value);
+#endif
 
   // Convenience forms of Append.
   void AppendBoolean(bool in_value);