Integrate pooled lambda with systrace.

Looper traces handler calls by calling Handler.getTraceName(), which when used with PooledLambda
ends up showing just:

"android.os.Handler: com.android.internal.util.function.pooled.PooledLambdaImpl"

That name doesn't help understand what's the real bottleneck, and even worse, could let people
think it's the PooledLambda who's causing it.

Which this change, it will display names like:

com.android.server.appop.AppOpsService$Lambda
com.android.server.wm$Lambda

Fixes: 141172840
Test: manual verification (neither PoolLambda nor Message have unit tests)

Change-Id: I80d2158a50a644b10f3724fb42a4a9c2aee63ae9

2 files changed, 35 insertions, 0 deletions

diff --git a/core/java/android/os/Handler.java b/core/java/android/os/Handler.java
index 9af9edae9a3f..45a9cf5ab869 100644
--- a/core/java/android/os/Handler.java
+++ b/core/java/android/os/Handler.java
@@ -295,6 +295,10 @@ public class Handler {
     /** {@hide} */
     @NonNull
     public String getTraceName(@NonNull Message message) {
+        if (message.callback instanceof TraceNameSupplier) {
+            return ((TraceNameSupplier) message.callback).getTraceName();
+        }
+
         final StringBuilder sb = new StringBuilder();
         sb.append(getClass().getName()).append(": ");
         if (message.callback != null) {
diff --git a/core/java/android/os/TraceNameSupplier.java b/core/java/android/os/TraceNameSupplier.java
new file mode 100644
index 000000000000..e4b3a4edce38
--- /dev/null
+++ b/core/java/android/os/TraceNameSupplier.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.os;
+
+import android.annotation.NonNull;
+
+/**
+ * Supplier for custom trace messages.
+ *
+ * @hide
+ */
+public interface TraceNameSupplier {
+
+    /**
+     * Gets the name used for trace messages.
+     */
+    @NonNull String getTraceName();
+}