Address PR comments.

Author: chinmaygarde

runtime/dart_isolate.cc

@@ -129,7 +129,7 @@ std::weak_ptr<DartIsolate> DartIsolate::CreateRunningRootIsolate(
 
   fml::ScopedCleanupClosure shutdown_on_error([isolate]() {
     if (!isolate->Shutdown()) {
-      FML_DLOG(ERROR) << "Could not transient isolate.";
+      FML_DLOG(ERROR) << "Could not shutdown transient isolate.";
     }
   });
 

runtime/dart_isolate.h

@@ -63,7 +63,7 @@ class DartIsolate : public UIDartState {
  public:
   class Flags {
    public:
-    explicit Flags();
+    Flags();
 
     explicit Flags(const Dart_IsolateFlags* flags);