Reduce memory churn from main thread looper tracing

Implement getTraceName() on two top Handlers on
the main thread Looper to avoid calls to getClass().getName()

Also avoids posting to main thread handler from the same thread in
FrameTracker callback

Bug: 285737625
Test: Manual - collect a trace and confirm main thread slice names
Change-Id: I7dbbd7702e339e8cf3e7c42d4df3762250e5aca5

core/java/android/view/Choreographer.java

@@ -34,6 +34,7 @@ import android.os.Message;
 import android.os.SystemClock;
 import android.os.SystemProperties;
 import android.os.Trace;
+import android.os.TraceNameSupplier;
 import android.util.Log;
 import android.util.TimeUtils;
 import android.view.animation.AnimationUtils;
@@ -1300,7 +1301,7 @@ public final class Choreographer {
     }
 
     private final class FrameDisplayEventReceiver extends DisplayEventReceiver
-            implements Runnable {
+            implements Runnable, TraceNameSupplier {
         private boolean mHavePendingVsync;
         private long mTimestampNanos;
         private int mFrame;
@@ -1358,6 +1359,14 @@ public final class Choreographer {
             mHavePendingVsync = false;
             doFrame(mTimestampNanos, mFrame, mLastVsyncEventData);
         }
+
+        @androidx.annotation.NonNull
+        @Override
+        public String getTraceName() {
+            // Returning just a simple name.
+            // More detailed logging happens in onVsync() for TRACE_TAG_VIEW.
+            return "FrameDisplayEventReceiver";
+        }
     }
 
     private static final class CallbackRecord {

core/java/android/view/ViewRootImpl.java

@@ -5787,6 +5787,15 @@ public final class ViewRootImpl implements ViewParent,
     private static final int MSG_PAUSED_FOR_SYNC_TIMEOUT = 37;
 
     final class ViewRootHandler extends Handler {
+        @androidx.annotation.NonNull
+        @Override
+        public String getTraceName(@androidx.annotation.NonNull Message message) {
+            if (message.getCallback() == null) {
+                return getMessageName(message);
+            }
+            return super.getTraceName(message);
+        }
+
         @Override
         public String getMessageName(Message message) {
             switch (message.what) {

core/java/com/android/internal/jank/FrameTracker.java

@@ -502,35 +502,35 @@ public class FrameTracker extends SurfaceControl.OnJankDataListener
         return vsyncId >= mBeginVsyncId;
     }
 
+    // This will be executed in the HardwareRendererObserver handler, which is the FrameTracker
+    // handler by construction.
     @Override
     public void onFrameMetricsAvailable(int dropCountSinceLastInvocation) {
-        postCallback(() -> {
-            if (mCancelled || mMetricsFinalized) {
-                return;
-            }
+        if (mCancelled || mMetricsFinalized) {
+            return;
+        }
 
-            // Since this callback might come a little bit late after the end() call.
-            // We should keep tracking the begin / end timestamp that we can compare with
-            // vsync timestamp to check if the frame is in the duration of the CUJ.
-            long totalDurationNanos = mMetricsWrapper.getMetric(FrameMetrics.TOTAL_DURATION);
-            boolean isFirstFrame = mMetricsWrapper.getMetric(FrameMetrics.FIRST_DRAW_FRAME) == 1;
-            long frameVsyncId =
-                    mMetricsWrapper.getTiming()[FrameMetrics.Index.FRAME_TIMELINE_VSYNC_ID];
+        // Since this callback might come a little bit late after the end() call.
+        // We should keep tracking the begin / end timestamp that we can compare with
+        // vsync timestamp to check if the frame is in the duration of the CUJ.
+        long totalDurationNanos = mMetricsWrapper.getMetric(FrameMetrics.TOTAL_DURATION);
+        boolean isFirstFrame = mMetricsWrapper.getMetric(FrameMetrics.FIRST_DRAW_FRAME) == 1;
+        long frameVsyncId =
+                mMetricsWrapper.getTiming()[FrameMetrics.Index.FRAME_TIMELINE_VSYNC_ID];
 
-            if (!isInRange(frameVsyncId)) {
-                return;
-            }
-            JankInfo info = findJankInfo(frameVsyncId);
-            if (info != null) {
-                info.hwuiCallbackFired = true;
-                info.totalDurationNanos = totalDurationNanos;
-                info.isFirstFrame = isFirstFrame;
-            } else {
-                mJankInfos.put((int) frameVsyncId, JankInfo.createFromHwuiCallback(
-                        frameVsyncId, totalDurationNanos, isFirstFrame));
-            }
-            processJankInfos();
-        });
+        if (!isInRange(frameVsyncId)) {
+            return;
+        }
+        JankInfo info = findJankInfo(frameVsyncId);
+        if (info != null) {
+            info.hwuiCallbackFired = true;
+            info.totalDurationNanos = totalDurationNanos;
+            info.isFirstFrame = isFirstFrame;
+        } else {
+            mJankInfos.put((int) frameVsyncId, JankInfo.createFromHwuiCallback(
+                    frameVsyncId, totalDurationNanos, isFirstFrame));
+        }
+        processJankInfos();
     }
 
     @UiThread