Implement get trap for proxies.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index eb7a4ce98a4ad3c1213f81c0e67a69a5070fb0c2..3620faed8e7a30d2c5aad47a93a6d237a8919fc9 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1638,10 +1638,12 @@ bool Genesis::InstallNatives() {
 
 
 bool Genesis::InstallExperimentalNatives() {
-  if (FLAG_harmony_proxies) {
-    for (int i = ExperimentalNatives::GetDebuggerCount();
-         i < ExperimentalNatives::GetBuiltinsCount();
-         i++) {
+  for (int i = ExperimentalNatives::GetDebuggerCount();
+       i < ExperimentalNatives::GetBuiltinsCount();
+       i++) {
+    if (FLAG_harmony_proxies &&
+        strcmp(ExperimentalNatives::GetScriptName(i).start(),
+               "native proxy.js") == 0) {
       if (!CompileExperimentalBuiltin(isolate(), i)) return false;
     }
   }
@@ -2004,8 +2006,9 @@ void Genesis::TransferNamedProperties(Handle<JSObject> from,
           break;
         case NORMAL:
           // Do not occur since the from object has fast properties.
+        case HANDLER:
         case INTERCEPTOR:
-          // No element in instance descriptors have interceptor type.
+          // No element in instance descriptors have proxy or interceptor type.
           UNREACHABLE();
           break;
       }