Revert recent CPU profiler changes because they broke --prof.

src/cpu-profiler-inl.h

Index: src/cpu-profiler-inl.h
diff --git a/src/cpu-profiler-inl.h b/src/cpu-profiler-inl.h
index 1133b20fcb7f26bdd8a923969aae556a86f95b0b..4982197cabaf418006431f15d107fa29e6af8f2a 100644
--- a/src/cpu-profiler-inl.h
+++ b/src/cpu-profiler-inl.h
@@ -31,6 +31,7 @@
 #include "cpu-profiler.h"
 
 #include <new>
+#include "circular-queue-inl.h"
 #include "profile-generator-inl.h"
 #include "unbound-queue-inl.h"
 
@@ -55,18 +56,11 @@ void SharedFunctionInfoMoveEventRecord::UpdateCodeMap(CodeMap* code_map) {
 }
 
 
-TickSample* ProfilerEventsProcessor::StartTickSampleEvent() {
-  if (!ticks_buffer_is_empty_ || ticks_buffer_is_initialized_) return NULL;
-  ticks_buffer_is_initialized_ = true;
+TickSample* ProfilerEventsProcessor::TickSampleEvent() {
   generator_->Tick();
-  ticks_buffer_ = TickSampleEventRecord(enqueue_order_);
-  return &ticks_buffer_.sample;
-}
-
-
-void ProfilerEventsProcessor::FinishTickSampleEvent() {
-  ASSERT(ticks_buffer_is_initialized_ && ticks_buffer_is_empty_);
-  ticks_buffer_is_empty_ = false;
+  TickSampleEventRecord* evt =
+      new(ticks_buffer_.Enqueue()) TickSampleEventRecord(enqueue_order_);
+  return &evt->sample;
 }