Initial GetSample implementation.

src/log.cc

Index: src/log.cc
diff --git a/src/log.cc b/src/log.cc
index 6d88a535dc78f4ce10ce7a578d56d1b7b32b4e7c..97bfe3def0c69ffc843d7fe26a328805a71dbb81 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -2060,6 +2060,13 @@ bool Logger::SetUp(Isolate* isolate) {
     profiler_->Engage();
   }
 
+  // TODO(gholap): This one's for the new sampler API. (include/v8-sampler.h)
+  //               Call to IncreaseProfilingDepth causes the
+  //               SIGPROF signal handler to be installed on the VM thread.
+  //               Figure out whether there's a way to only optionally
+  //               do this based on a runtime flag.
+  ticker_->IncreaseProfilingDepth();
+
   if (FLAG_log_internal_timer_events || FLAG_prof) timer_.Start();
 
   return true;