Add a sampling profiler and a script to generate profiles for use with Gecko tooling.

components/msg/constellation_msg.rs

@@ -350,6 +350,24 @@ pub enum HangAnnotation {
     Script(ScriptHangAnnotation),
 }
 
+/// Hang-alerts are sent by the monitor to the constellation.
+#[derive(Deserialize, Serialize)]
+pub enum HangMonitorAlert {
+    /// A component hang has been detected.
+    Hang(HangAlert),
+    /// Report a completed sampled profile.
+    Profile(Vec<u8>),
+}
+
+impl fmt::Debug for HangMonitorAlert {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            HangMonitorAlert::Hang(..) => write!(fmt, "Hang"),
+            HangMonitorAlert::Profile(..) => write!(fmt, "Profile"),
+        }
+    }
+}
+
 /// Hang-alerts are sent by the monitor to the constellation.
 #[derive(Deserialize, Serialize)]
 pub enum HangAlert {