Adds Serial API to set data bits, parity, stop bits.

chrome/common/extensions/api/serial.idl

Index: chrome/common/extensions/api/serial.idl
===================================================================
--- chrome/common/extensions/api/serial.idl	(revision 218161)
+++ chrome/common/extensions/api/serial.idl	(working copy)
@@ -8,6 +8,10 @@
 
   callback GetPortsCallback = void (DOMString[] ports);
 
+  enum DataBit { sevenbit, eightbit };
+  enum ParityBit { noparity, oddparity, evenparity };
+  enum StopBit { onestopbit, twostopbit };
+
   dictionary OpenOptions {
     // The requested bitrate of the connection to be opened. For compatibility
     // with the widest range of hardware, this number should match one of
@@ -15,7 +19,10 @@
     // 14400, 19200, 38400, 57600, 115200. There is no guarantee, of course,
     // that the device connected to the serial port will support the requested
     // bitrate, even if the port itself supports that bitrate.
-    long bitrate;
+    long? bitrate;

[miket_OOO, 2013/08/21 19:43:44]

It's OK if we make bitrate optional, but we should document here that the
default is 9600. Otherwise people will have to guess it.

[limasdf, 2013/08/24 15:46:24]

Done.

+    DataBit? dataBit;
+    ParityBit? parityBit;
+    StopBit? stopBit;
   };
 
   dictionary OpenInfo {