Don't use in-class initialization of non-static data members. It's a C++11 extension.

runtime/vm/kernel_to_il.h

Index: runtime/vm/kernel_to_il.h
diff --git a/runtime/vm/kernel_to_il.h b/runtime/vm/kernel_to_il.h
index ccf4801a81e0055ec34d0ec86104be8098d94c57..6f50949e500feaca4a3b5aa9527b9105f7ab10ce 100644
--- a/runtime/vm/kernel_to_il.h
+++ b/runtime/vm/kernel_to_il.h
@@ -382,34 +382,43 @@ struct FunctionScope {
 
 class ScopeBuildingResult : public ZoneAllocated {
  public:
+  ScopeBuildingResult()
+    : this_variable(NULL),
+      type_arguments_variable(NULL),
+      switch_variable(NULL),
+      finally_return_variable(NULL),
+      setter_value(NULL),
+      yield_jump_variable(NULL),
+      yield_context_variable(NULL) {}
+
   Map<VariableDeclaration, LocalVariable*> locals;
   Map<TreeNode, LocalScope*> scopes;
   GrowableArray<FunctionScope> function_scopes;
 
   // Only non-NULL for instance functions.
-  LocalVariable* this_variable = NULL;
+  LocalVariable* this_variable;
 
   // Only non-NULL for factory constructor functions.
-  LocalVariable* type_arguments_variable = NULL;
+  LocalVariable* type_arguments_variable;
 
   // Non-NULL when the function contains a switch statement.
-  LocalVariable* switch_variable = NULL;
+  LocalVariable* switch_variable;
 
   // Non-NULL when the function contains a return inside a finally block.
-  LocalVariable* finally_return_variable = NULL;
+  LocalVariable* finally_return_variable;
 
   // Non-NULL when the function is a setter.
-  LocalVariable* setter_value = NULL;
+  LocalVariable* setter_value;
 
   // Non-NULL if the function contains yield statement.
   // TODO(27590) actual variable is called :await_jump_var, we should rename
   // it to reflect the fact that it is used for both await and yield.
-  LocalVariable* yield_jump_variable = NULL;
+  LocalVariable* yield_jump_variable;
 
   // Non-NULL if the function contains yield statement.
   // TODO(27590) actual variable is called :await_ctx_var, we should rename
   // it to reflect the fact that it is used for both await and yield.
-  LocalVariable* yield_context_variable = NULL;
+  LocalVariable* yield_context_variable;
 
   // Variables used in exception handlers, one per exception handler nesting
   // level.