Profiler fixes

runtime/vm/profiler_android.cc

Index: runtime/vm/profiler_android.cc
diff --git a/runtime/vm/profiler_android.cc b/runtime/vm/profiler_android.cc
index 1392739ddc066e6141c6cdd312df4b24a7f8d1e5..5d9167cadae2d8bf42a07feb79b57394445e0737 100644
--- a/runtime/vm/profiler_android.cc
+++ b/runtime/vm/profiler_android.cc
@@ -28,13 +28,15 @@ static void ProfileSignalAction(int signal, siginfo_t* info, void* context_) {
     // Thread owns isolate profiler data mutex.
     ScopedMutex profiler_data_lock(isolate->profiler_data_mutex());
     IsolateProfilerData* profiler_data = isolate->profiler_data();
-    if (profiler_data == NULL) {
-      return;
-    }
-    if (!profiler_data->CanExpire()) {
+    if ((profiler_data == NULL) || !profiler_data->CanExpire() ||
+        (profiler_data->sample_buffer() == NULL)) {
       // Descheduled.
       return;
     }
+    if (profiler_data->thread_id() == Thread::GetCurrentThreadId()) {
+      // Still scheduled on this thread.
+      // TODO(johnmccutchan): Perform sample on Android.
+    }
   }
   // Thread owns no profiler locks at this point.
   // This call will acquire both ProfilerManager::monitor and the