Fix gperftools to not arm the profiling timer by default.

third_party/tcmalloc/chromium/src/profiler.cc

Index: third_party/tcmalloc/chromium/src/profiler.cc
diff --git a/third_party/tcmalloc/chromium/src/profiler.cc b/third_party/tcmalloc/chromium/src/profiler.cc
index dfb6aab52f4a9d7aa0e6e9c9a0a596c24e322efd..65879f6afa40d9c30d1b01796a6520cc8e585c30 100644
--- a/third_party/tcmalloc/chromium/src/profiler.cc
+++ b/third_party/tcmalloc/chromium/src/profiler.cc
@@ -290,6 +290,10 @@ extern "C" PERFTOOLS_DLL_DECL void ProfilerRegisterThread() {
   ProfileHandlerRegisterThread();
 }
 
+extern "C" PERFTOOLS_DLL_DECL void ProfilerUnregisterThread() {
+  ProfileHandlerUnregisterThread();
+}
+
 extern "C" PERFTOOLS_DLL_DECL void ProfilerFlush() {
   CpuProfiler::instance_.FlushTable();
 }
@@ -323,6 +327,7 @@ extern "C" PERFTOOLS_DLL_DECL void ProfilerGetCurrentState(
 // these issues, unless a specific need is identified, profiler support is
 // disabled under Cygwin.
 extern "C" void ProfilerRegisterThread() { }
+extern "C" void ProfilerUnregisterThread() { }
 extern "C" void ProfilerFlush() { }
 extern "C" int ProfilingIsEnabledForAllThreads() { return 0; }
 extern "C" int ProfilerStart(const char* fname) { return 0; }