Add Dart_Save/LoadCompilationTrace.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 0446fa78fdd2db4a346817324f257d93dfc425ef..296a26e867f866bbefed92ab62949e367cb4afc5 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -10850,6 +10850,26 @@ RawClass* Library::LookupClassAllowPrivate(const String& name) const {
 }
 
 
+// Mixin applications can have multiple private keys from different libraries.
+RawClass* Library::SlowLookupClassAllowMultiPartPrivate(
+    const String& name) const {
+  Array& dict = Array::Handle(dictionary());
+  Object& entry = Object::Handle();
+  String& cls_name = String::Handle();
+  for (intptr_t i = 0; i < dict.Length(); i++) {
+    entry = dict.At(i);
+    if (entry.IsClass()) {
+      cls_name = Class::Cast(entry).Name();
+      // Warning: comparison is not symmetric.
+      if (String::EqualsIgnoringPrivateKey(cls_name, name)) {
+        return Class::Cast(entry).raw();
+      }
+    }
+  }
+  return Class::null();
+}
+
+
 RawLibraryPrefix* Library::LookupLocalLibraryPrefix(const String& name) const {
   const Object& obj = Object::Handle(LookupLocalObject(name));
   if (obj.IsLibraryPrefix()) {