Move FrameMetricsObserver logic into UI Module.

Introduce HardwareRendererObserver to isolate the android.graphics
package from the android.view package.  The native code that
interacts with the observer was also moved from libandroid_runtime to
libandroid_graphics to keep it within the confines of the UI Rendering
module.

Bug: 137655431
Test: CtsUiRenderingTestCases
Change-Id: Ibccecbeda0c4d9501d86514a53eb98548233ba6a

graphics/java/android/graphics/HardwareRenderer.java

@@ -28,7 +28,6 @@ import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.util.Log;
 import android.util.TimeUtils;
-import android.view.FrameMetricsObserver;
 import android.view.IGraphicsStats;
 import android.view.IGraphicsStatsCallback;
 import android.view.NativeVectorDrawableAnimator;
@@ -38,8 +37,6 @@ import android.view.SurfaceHolder;
 import android.view.TextureLayer;
 import android.view.animation.AnimationUtils;
 
-import com.android.internal.util.VirtualRefBasePtr;
-
 import java.io.File;
 import java.io.FileDescriptor;
 import java.lang.annotation.Retention;
@@ -598,9 +595,8 @@ public class HardwareRenderer {
      *
      * @hide
      */
-    public void addFrameMetricsObserver(FrameMetricsObserver observer) {
-        long nativeObserver = nAddFrameMetricsObserver(mNativeProxy, observer);
-        observer.mNative = new VirtualRefBasePtr(nativeObserver);
+    public void addObserver(HardwareRendererObserver observer) {
+        nAddObserver(mNativeProxy, observer.getNativeInstance());
     }
 
     /**
@@ -608,9 +604,8 @@ public class HardwareRenderer {
      *
      * @hide
      */
-    public void removeFrameMetricsObserver(FrameMetricsObserver observer) {
-        nRemoveFrameMetricsObserver(mNativeProxy, observer.mNative.get());
-        observer.mNative = null;
+    public void removeObserver(HardwareRendererObserver observer) {
+        nRemoveObserver(mNativeProxy, observer.getNativeInstance());
     }
 
     /**
@@ -1170,10 +1165,9 @@ public class HardwareRenderer {
     private static native void nSetFrameCompleteCallback(long nativeProxy,
             FrameCompleteCallback callback);
 
-    private static native long nAddFrameMetricsObserver(long nativeProxy,
-            FrameMetricsObserver observer);
+    private static native void nAddObserver(long nativeProxy, long nativeObserver);
 
-    private static native void nRemoveFrameMetricsObserver(long nativeProxy, long nativeObserver);
+    private static native void nRemoveObserver(long nativeProxy, long nativeObserver);
 
     private static native int nCopySurfaceInto(Surface surface,
             int srcLeft, int srcTop, int srcRight, int srcBottom, long bitmapHandle);

graphics/java/android/graphics/HardwareRendererObserver.java

@@ -0,0 +1,103 @@
+/*
+ * 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.graphics;
+
+import android.annotation.NonNull;
+import android.os.Handler;
+
+import com.android.internal.util.VirtualRefBasePtr;
+
+/**
+ * Provides streaming access to frame stats information from HardwareRenderer to apps.
+ *
+ * @hide
+ */
+public class HardwareRendererObserver {
+    private final long[] mFrameMetrics;
+    private final Handler mHandler;
+    private final OnFrameMetricsAvailableListener mListener;
+    private VirtualRefBasePtr mNativePtr;
+
+    /**
+     * Interface for clients that want frame timing information for each frame rendered.
+     * @hide
+     */
+    public interface OnFrameMetricsAvailableListener {
+        /**
+         * Called when information is available for the previously rendered frame.
+         *
+         * Reports can be dropped if this callback takes too long to execute, as the report producer
+         * cannot wait for the consumer to complete.
+         *
+         * It is highly recommended that clients copy the metrics array within this method
+         * and defer additional computation or storage to another thread to avoid unnecessarily
+         * dropping reports.
+         *
+         * @param dropCountSinceLastInvocation the number of reports dropped since the last time
+         * this callback was invoked.
+         */
+        void onFrameMetricsAvailable(int dropCountSinceLastInvocation);
+    }
+
+    /**
+     * Creates a FrameMetricsObserver
+     *
+     * @param frameMetrics the available metrics. This array is reused on every call to the listener
+     * and thus <strong>this reference should only be used within the scope of the listener callback
+     * as data is not guaranteed to be valid outside the scope of that method</strong>.
+     * @param handler the Handler to use when invoking callbacks
+     */
+    public HardwareRendererObserver(@NonNull OnFrameMetricsAvailableListener listener,
+            @NonNull long[] frameMetrics, @NonNull Handler handler) {
+        if (handler == null || handler.getLooper() == null) {
+            throw new NullPointerException("handler and its looper cannot be null");
+        }
+
+        if (handler.getLooper().getQueue() == null) {
+            throw new IllegalStateException("invalid looper, null message queue\n");
+        }
+
+        mFrameMetrics = frameMetrics;
+        mHandler = handler;
+        mListener = listener;
+        mNativePtr = new VirtualRefBasePtr(nCreateObserver());
+    }
+
+    /*package*/ long getNativeInstance() {
+        return mNativePtr.get();
+    }
+
+    // Called by native on the provided Handler
+    @SuppressWarnings("unused")
+    private void notifyDataAvailable() {
+        mHandler.post(() -> {
+            boolean hasMoreData = true;
+            while (hasMoreData) {
+                // a drop count of -1 is a sentinel that no more buffers are available
+                int dropCount = nGetNextBuffer(mNativePtr.get(), mFrameMetrics);
+                if (dropCount >= 0) {
+                    mListener.onFrameMetricsAvailable(dropCount);
+                } else {
+                    hasMoreData = false;
+                }
+            }
+        });
+    }
+
+    private native long nCreateObserver();
+    private static native int nGetNextBuffer(long nativePtr, long[] data);
+}