Merged r11230, r11241, r11283, r11405 into 3.9 branch.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 918a2a679b6b6e3b27b04cb4fb4bb43b288b3e02..f960b5869101399e691d88463fd81fa3cbd7cb0a 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -62,6 +62,10 @@ class AssemblerBase: public Malloced {
   Isolate* isolate() const { return isolate_; }
   int jit_cookie() { return jit_cookie_; }
 
+  // Overwrite a host NaN with a quiet target NaN.  Used by mksnapshot for
+  // cross-snapshotting.
+  static void QuietNaN(HeapObject* nan) { }
+
  private:
   Isolate* isolate_;
   int jit_cookie_;