Use a class field instead of global FLAG_debug_code in assember and

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index b60157c752d2d7670672a016658f5998c194c405..7d9e3749137a78c94c3de6a21dfd4a8005494a90 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -522,6 +522,9 @@ class Assembler : public Malloced {
   Assembler(void* buffer, int buffer_size);
   ~Assembler();
 
+  // Overrides the default provided by FLAG_debug_code.
+  void set_emit_debug_code(bool value) { emit_debug_code_ = value; }
+
   // GetCode emits any pending (non-emitted) code and fills the descriptor
   // desc. GetCode() is idempotent; it returns the same result if no other
   // Assembler functions are invoked in between GetCode() calls.
@@ -982,6 +985,8 @@ class Assembler : public Malloced {
   static const int kMinimalBufferSize = 4*KB;
 
  protected:
+  bool emit_debug_code() const { return emit_debug_code_; }
+
   void movsd(XMMRegister dst, const Operand& src);
   void movsd(const Operand& dst, XMMRegister src);
 
@@ -1057,6 +1062,8 @@ class Assembler : public Malloced {
 
   PositionsRecorder positions_recorder_;
 
+  bool emit_debug_code_;
+
   friend class PositionsRecorder;
 };