Reduce the space used by the stack for the profiling thread.

src/platform.h

Index: src/platform.h
===================================================================
--- src/platform.h	(revision 10489)
+++ src/platform.h	(working copy)
@@ -412,16 +412,22 @@
     LOCAL_STORAGE_KEY_MAX_VALUE = kMaxInt
   };
 
-  struct Options {
-    Options() : name("v8:<unknown>"), stack_size(0) {}
+  class Options {
+   public:
+    Options() : name_("v8:<unknown>"), stack_size_(0) {}
+    Options(const char* name, int stack_size = 0)
+        : name_(name), stack_size_(stack_size) {}
 
-    const char* name;
-    int stack_size;
+    const char* name() const { return name_; }
+    int stack_size() const { return stack_size_; }
+
+   private:
+    const char* name_;
+    int stack_size_;
   };
 
   // Create new thread.
   explicit Thread(const Options& options);
-  explicit Thread(const char* name);
   virtual ~Thread();
 
   // Start new thread by calling the Run() method in the new thread.