Avoid unspecified behavior in SkiaBitmapDesktopFrame::Create

remoting/host/chromeos/skia_bitmap_desktop_frame.cc

Index: remoting/host/chromeos/skia_bitmap_desktop_frame.cc
diff --git a/remoting/host/chromeos/skia_bitmap_desktop_frame.cc b/remoting/host/chromeos/skia_bitmap_desktop_frame.cc
index d32f387e2cf14426f64cdba7052488d1d16e101d..9be841f2d092822b43b44b4bcc97f632badfe5a6 100644
--- a/remoting/host/chromeos/skia_bitmap_desktop_frame.cc
+++ b/remoting/host/chromeos/skia_bitmap_desktop_frame.cc
@@ -19,8 +19,9 @@ SkiaBitmapDesktopFrame* SkiaBitmapDesktopFrame::Create(
   uint8_t* bitmap_data = reinterpret_cast<uint8_t*>(bitmap->getPixels());
   bitmap->unlockPixels();
 
+  const size_t row_bytes = bitmap->rowBytes();
   SkiaBitmapDesktopFrame* result = new SkiaBitmapDesktopFrame(
-      size, bitmap->rowBytes(), bitmap_data, bitmap.Pass());
+      size, row_bytes, bitmap_data, bitmap.Pass());
 
   return result;
 }