Implement a PerformanceActor.

This is necessary for the devtools "Start Recording Performance" button to
send a message.

(This message is not yet supported, so it leads to
'unexpected message type "startRecording" found for actor "performance4"'.)

components/devtools/actors/performance.rs

@@ -0,0 +1,73 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use actor::{Actor, ActorRegistry, ActorMessageStatus};
+use protocol::JsonPacketStream;
+
+use rustc_serialize::json;
+use std::net::TcpStream;
+
+pub struct PerformanceActor {
+    name: String,
+}
+
+#[derive(RustcEncodable)]
+struct PerformanceFeatures {
+    withMarkers: bool,
+    withMemory: bool,
+    withTicks: bool,
+    withAllocations: bool,
+    withJITOptimizations: bool,
+}
+
+#[derive(RustcEncodable)]
+struct PerformanceTraits {
+    features: PerformanceFeatures,
+}
+
+#[derive(RustcEncodable)]
+struct ConnectReply {
+    from: String,
+    traits: PerformanceTraits,
+}
+
+impl Actor for PerformanceActor {
+    fn name(&self) -> String {
+        self.name.clone()
+    }
+
+    fn handle_message(&self,
+                      _registry: &ActorRegistry,
+                      msg_type: &str,
+                      _msg: &json::Object,
+                      stream: &mut TcpStream) -> Result<ActorMessageStatus, ()> {
+        Ok(match msg_type {
+            "connect" => {
+                let msg = ConnectReply {
+                    from: self.name(),
+                    traits: PerformanceTraits {
+                        features: PerformanceFeatures {
+                            withMarkers: true,
+                            withMemory: true,
+                            withTicks: true,
+                            withAllocations: true,
+                            withJITOptimizations: true,
+                        },
+                    },
+                };
+                stream.write_json_packet(&msg);
+                ActorMessageStatus::Processed
+            },
+            _ => ActorMessageStatus::Ignored,
+        })
+    }
+}
+
+impl PerformanceActor {
+    pub fn new(name: String) -> PerformanceActor {
+        PerformanceActor {
+            name: name,
+        }
+    }
+}

components/devtools/actors/tab.rs

@@ -63,6 +63,7 @@ pub struct TabActorMsg {
     inspectorActor: String,
     timelineActor: String,
     profilerActor: String,
+    performanceActor: String,
 }
 
 pub struct TabActor {
@@ -73,6 +74,7 @@ pub struct TabActor {
     pub inspector: String,
     pub timeline: String,
     pub profiler: String,
+    pub performance: String,
 }
 
 impl Actor for TabActor {
@@ -150,6 +152,7 @@ impl TabActor {
             inspectorActor: self.inspector.clone(),
             timelineActor: self.timeline.clone(),
             profilerActor: self.profiler.clone(),
+            performanceActor: self.performance.clone(),
         }
     }
 }