Fix RecordStackTraceAtStartProfiling test.

test/cctest/test-profile-generator.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 //
 // Tests of profiles generator and utilities.
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
 
 #include "v8.h"
 #include "profile-generator-inl.h"
 #include "cctest.h"
 #include "../include/v8-profiler.h"
@@ skipping 764 matching lines @@
       "function c() { startProfiling(); }\n"
       "function b() { c(); }\n"
       "function a() { b(); }\n"
       "a();\n"
       "stopProfiling();");
   CHECK_EQ(1, CpuProfiler::GetProfilesCount());
   CpuProfile* profile =
       CpuProfiler::GetProfile(NULL, 0);
   const ProfileTree* topDown = profile->top_down();
   const ProfileNode* current = topDown->root();
+  const_cast<ProfileNode*>(current)->Print(0);
   // The tree should look like this:
   //  (root)
   //   (anonymous function)
   //     a
   //       b
   //         c
+  // There can also be:
+  //           startProfiling
+  // if the sampler managed to get a tick.
   current = PickChild(current, "(anonymous function)");
   CHECK_NE(NULL, const_cast<ProfileNode*>(current));
   current = PickChild(current, "a");
   CHECK_NE(NULL, const_cast<ProfileNode*>(current));
   current = PickChild(current, "b");
   CHECK_NE(NULL, const_cast<ProfileNode*>(current));
   current = PickChild(current, "c");
   CHECK_NE(NULL, const_cast<ProfileNode*>(current));
-  CHECK_EQ(0, current->children()->length());
+  CHECK(current->children()->length() == 0 ||
+        current->children()->length() == 1);
+  if (current->children()->length() == 1) {
+    current = PickChild(current, "startProfiling");
+    CHECK_EQ(0, current->children()->length());
+  }
 }
 
 
 TEST(Issue51919) {
   CpuProfilesCollection collection;
   i::EmbeddedVector<char*,
       CpuProfilesCollection::kMaxSimultaneousProfiles> titles;
   for (int i = 0; i < CpuProfilesCollection::kMaxSimultaneousProfiles; ++i) {
     i::Vector<char> title = i::Vector<char>::New(16);
     i::OS::SNPrintF(title, "%d", i);
     CHECK(collection.StartProfiling(title.start(), i + 1));  // UID must be > 0.
     titles[i] = title.start();
   }
   CHECK(!collection.StartProfiling(
       "maximum", CpuProfilesCollection::kMaxSimultaneousProfiles + 1));
   for (int i = 0; i < CpuProfilesCollection::kMaxSimultaneousProfiles; ++i)
     i::DeleteArray(titles[i]);
 }
 
 #endif  // ENABLE_LOGGING_AND_PROFILING