Port StorageThreadMsg to GenericChannel (#38932)

This change includes the following additions to GenericChannel:
- Add a GenericSend trait which is meant to replace the `IpcSend` trait
over time, as channels are migrated. For the time being this means, that
we often need to use `GenericSend::send()` to disambiguate from the
`IpcSend::send` function, until all usages of `IpcSend` have been
replaced.
- Add an OpaqueSender impl for GenericSender
- Add a profiled version of GenericChannel. The profiling is 1:1 the
same as for the existing profiled IPC channel, namely that only the
blocked time during `recv` is measured.


Testing: No functional changes, covered by existing tests
Part of #38912

---------

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>

components/shared/profile/mem.rs

@@ -11,6 +11,7 @@ use std::collections::HashSet;
 use std::ffi::c_void;
 use std::marker::Send;
 
+use base::generic_channel::GenericSender;
 use crossbeam_channel::Sender;
 use ipc_channel::ipc::{self, IpcSender};
 use ipc_channel::router::ROUTER;
@@ -49,6 +50,20 @@ where
     }
 }
 
+impl<T> OpaqueSender<T> for GenericSender<T>
+where
+    T: serde::Serialize,
+{
+    fn send(&self, message: T) {
+        if let Err(e) = GenericSender::send(self, message) {
+            warn!(
+                "Error communicating with the target thread from the profiler: {}",
+                e
+            );
+        }
+    }
+}
+
 /// Front-end representation of the profiler used to communicate with the
 /// profiler.
 #[derive(Clone, Debug, Deserialize, Serialize)]