Track per-window information in ViewFrameInfo

FrameInfo will now be per-window; that is, per-ViewRootImpl.
Some of the information should remain “global” (it remain in Choreographer),
while some information is going to become ViewRootImpl-specific.
Before the information gets passed to the native layer,
 the ViewRootImpl-specific info will be stitched together
with the general Choreographer info.

This change is useful in order to correctly correlate frames with a specific
input event. In the unlikely scenario of a user touching two windows of the
same app simultaneously, this change will allow us to correctly measure the
latency of both frames produced by the windows.

Design doc: https://docs.google.com/document/d/1KMpMBlOxnl7zkWBCbXZZE6ZlaHEA4efYnN6WYK8n3FE/edit?resourcekey=0-eqooVNP0SskupljlTFvtOQ

Test: atest ViewFrameInfoTest
Bug: 169866723
Change-Id: Ib0bf9cd51cbcc0b9b70460c929c480eb490ec322

1 files changed, 81 insertions, 0 deletions

diff --git a/core/java/android/view/ViewFrameInfo.java b/core/java/android/view/ViewFrameInfo.java
new file mode 100644
index 000000000000..890d071f8090
--- /dev/null
+++ b/core/java/android/view/ViewFrameInfo.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2020 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.view;
+
+import android.graphics.FrameInfo;
+
+/**
+ * The timing information of events taking place in ViewRootImpl
+ * @hide
+ */
+public class ViewFrameInfo {
+    public long drawStart;
+    public long oldestInputEventTime; // the time of the oldest input event consumed for this frame
+    public long newestInputEventTime; // the time of the newest input event consumed for this frame
+    // Various flags set to provide extra metadata about the current frame. See flag definitions
+    // inside FrameInfo.
+    // @see android.graphics.FrameInfo.FLAG_WINDOW_LAYOUT_CHANGED
+    public long flags;
+
+    /**
+     * Update the oldest event time.
+     * @param eventTime the time of the input event
+     */
+    public void updateOldestInputEvent(long eventTime) {
+        if (oldestInputEventTime == 0 || eventTime < oldestInputEventTime) {
+            oldestInputEventTime = eventTime;
+        }
+    }
+
+    /**
+     * Update the newest event time.
+     * @param eventTime the time of the input event
+     */
+    public void updateNewestInputEvent(long eventTime) {
+        if (newestInputEventTime == 0 || eventTime > newestInputEventTime) {
+            newestInputEventTime = eventTime;
+        }
+    }
+
+    /**
+     * Populate the missing fields using the data from ViewFrameInfo
+     * @param frameInfo : the structure FrameInfo object to populate
+     */
+    public void populateFrameInfo(FrameInfo frameInfo) {
+        frameInfo.frameInfo[FrameInfo.FLAGS] |= flags;
+        frameInfo.frameInfo[FrameInfo.DRAW_START] = drawStart;
+        frameInfo.frameInfo[FrameInfo.OLDEST_INPUT_EVENT] = oldestInputEventTime;
+        frameInfo.frameInfo[FrameInfo.NEWEST_INPUT_EVENT] = newestInputEventTime;
+    }
+
+    /**
+     * Reset this data. Should typically be invoked after calling "populateFrameInfo".
+     */
+    public void reset() {
+        drawStart = 0;
+        oldestInputEventTime = 0;
+        newestInputEventTime = 0;
+        flags = 0;
+    }
+
+    /**
+     * Record the current time, and store it in 'drawStart'
+     */
+    public void markDrawStart() {
+        drawStart = System.nanoTime();
+    }
+}