Allow for no samples in test-cpu-profiler/SampleWhenFrameIsNotSetup

test/cctest/test-cpu-profiler.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 590 matching lines @@
 
   const v8::CpuProfileNode* root = profile->GetTopDownRoot();
 
   ScopedVector<v8::Handle<v8::String> > names(3);
   names[0] = v8::String::New(ProfileGenerator::kGarbageCollectorEntryName);
   names[1] = v8::String::New(ProfileGenerator::kProgramEntryName);
   names[2] = v8::String::New("start");
   CheckChildrenNames(root, names);
 
   const v8::CpuProfileNode* startNode = FindChild(root, "start");
-  if (startNode->GetChildrenCount() > 0) {
+  // On slow machines there may be no meaningfull samples at all, skip the
+  // check there.
+  if (startNode && startNode->GetChildrenCount() > 0) {
     CHECK_EQ(1, startNode->GetChildrenCount());
     const v8::CpuProfileNode* delayNode = FindChild(startNode, "delay");
     if (delayNode->GetChildrenCount() > 0) {
       CHECK_EQ(1, delayNode->GetChildrenCount());
       FindChild(delayNode, "loop");
     }
   }
 
   cpu_profiler->DeleteAllCpuProfiles();
 }