EDK: Make PlatformChannelPair not depend/use on base::CommandLine.

(Now it doesn't need to use any command line class at all.)

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/1431203002 .
diff --git a/shell/child_switches.cc b/shell/child_switches.cc
index 85f31c9..ef47412 100644
--- a/shell/child_switches.cc
+++ b/shell/child_switches.cc
@@ -10,4 +10,9 @@
 // |ConnectToMaster()| for its |platform_connection_id| argument.
 const char kChildConnectionId[] = "child-connection-id";
 
+// The value of this switch is the string that was produced by
+// |PlatformChannelPair::PrepareToPassClientHandleToChildProcess()| and should
+// be given to |PlatformChannelPair::PassClientHandleFromParentProcess()|.
+const char kPlatformChannelHandleInfo[] = "platform-channel-handle-info";
+
 }  // namespace switches