Make PlatformChannelPair "dumb".

shell/child_switches.cc

Index: shell/child_switches.cc
diff --git a/shell/child_switches.cc b/shell/child_switches.cc
index ef474124322f281ca32212642dd03dffd032f0cf..85f31c909ed56bb7132e74a312d858a183b1bb67 100644
--- a/shell/child_switches.cc
+++ b/shell/child_switches.cc
@@ -10,9 +10,4 @@ namespace switches {
 // |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