Moving cpu profiling into its own thread.

src/platform.h

Index: src/platform.h
diff --git a/src/platform.h b/src/platform.h
index 14f4551f372e2c5faed9e9f8312ad1ab84a0c519..e9d3498e8a77f3cd5a7b762da415c45a9d0e8a1b 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -763,6 +763,32 @@ class Sampler {
 };
 
 
+// ----------------------------------------------------------------------------
+// CpuProfilerThread
+//
+
+class CpuProfilerThread : public Thread {
+ public:
+  static const int kCpuProfilerThreadStackSize = 64 * KB;
+
+  explicit CpuProfilerThread(Sampler* sampler);
+  virtual ~CpuProfilerThread();
+
+  virtual void Run() = 0;
+
+  void DoSample();
+
+  class PlatformData;
+  PlatformData* data() { return data_; }
+
+  PlatformData* platform_data() { return data_; }
+
+ private:
+  PlatformData* data_;  // Platform specific data.
+  Sampler* sampler_;
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_