Always use ChannelMojo for content child processes.

content/common/in_process_child_thread_params.cc

Index: content/common/in_process_child_thread_params.cc
diff --git a/content/common/in_process_child_thread_params.cc b/content/common/in_process_child_thread_params.cc
index 79cd7e8f0b0e080a9dab8a1cad5a088c483f451a..c8723bf215f205127cd6d155cb5afa0e435ee612 100644
--- a/content/common/in_process_child_thread_params.cc
+++ b/content/common/in_process_child_thread_params.cc
@@ -7,11 +7,9 @@
 namespace content {
 
 InProcessChildThreadParams::InProcessChildThreadParams(
-    const std::string& channel_name,
     scoped_refptr<base::SequencedTaskRunner> io_runner,
     const std::string& application_token)
-    : channel_name_(channel_name), io_runner_(io_runner),
-      application_token_(application_token) {}
+    : io_runner_(io_runner), application_token_(application_token) {}
 
 InProcessChildThreadParams::InProcessChildThreadParams(
     const InProcessChildThreadParams& other) = default;