vm-service: Add optional 'scope' parameter to 'evaluate' and 'evaluateInFrame'.

runtime/vm/debugger.cc

Index: runtime/vm/debugger.cc
diff --git a/runtime/vm/debugger.cc b/runtime/vm/debugger.cc
index 2bd07a4ba09af7f89d7ad6a6f8d5fb33a313a8b6..2e68d750ebd704f1a62deaa1f7fc4dfc83015275 100644
--- a/runtime/vm/debugger.cc
+++ b/runtime/vm/debugger.cc
@@ -1284,13 +1284,12 @@ static bool IsPrivateVariableName(const String& var_name) {
 }
 
 
-RawObject* ActivationFrame::Evaluate(const String& expr) {
+RawObject* ActivationFrame::Evaluate(const String& expr,
+                                     const GrowableObjectArray& param_names,
+                                     const GrowableObjectArray& param_values) {
   GetDescIndices();
-  const GrowableObjectArray& param_names =
-      GrowableObjectArray::Handle(GrowableObjectArray::New());
-  const GrowableObjectArray& param_values =
-      GrowableObjectArray::Handle(GrowableObjectArray::New());
   String& name = String::Handle();
+  String& existing_name = String::Handle();
   Object& value = Instance::Handle();
   intptr_t num_variables = desc_indices_.length();
   for (intptr_t i = 0; i < num_variables; i++) {
@@ -1300,8 +1299,18 @@ RawObject* ActivationFrame::Evaluate(const String& expr) {
       if (IsPrivateVariableName(name)) {
         name = String::ScrubName(name);
       }
-      param_names.Add(name);
-      param_values.Add(value);
+      bool conflict = false;
+      for (intptr_t j = 0; j < param_names.Length(); j++) {
+        existing_name ^= param_names.At(j);
+        if (name.Equals(existing_name)) {
+          conflict = true;
+          break;
+        }
+      }
+      if (!conflict) {
+        param_names.Add(name);
+        param_values.Add(value);
+      }

[siva, 2017/05/18 20:56:48]

if there are conflicts what happens do we get an exception?

We should add a test case with conflicting parameter names.

[rmacnak, 2017/05/19 00:56:44]

This code says if there is a local 'x' and value in the user-provided scope 'x',
the 'x' from the user provided scope wins. This case is included in
evaluate_in_frame_with_scope_test.dart. Added comment here.

     }
   }
 
@@ -1655,8 +1664,7 @@ void Debugger::Shutdown() {
 }
 
 
-void Debugger::OnIsolateRunnable() {
-}
+void Debugger::OnIsolateRunnable() {}
 
 
 static RawFunction* ResolveLibraryFunction(const Library& library,