1 files changed, 70 insertions, 45 deletions

diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 30bb2bbd3385..16de906b1085 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -68,6 +68,7 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.Debug;
 import android.os.Handler;
+import android.os.IBinder;
 import android.os.Looper;
 import android.os.Message;
 import android.os.ParcelFileDescriptor;
@@ -476,17 +477,19 @@ public final class ViewRootImpl implements ViewParent,
     @UnsupportedAppUsage
     public final Surface mSurface = new Surface();
     private final SurfaceControl mSurfaceControl = new SurfaceControl();
+    private IBinder mPreviousSurfaceControlHandle = null;
+
+    private final Transaction mChangeSurfaceTransaction = new Transaction();
+    private final SurfaceSession mSurfaceSession = new SurfaceSession();
 
     /**
-     * Child surface of {@code mSurface} with the same bounds as its parent, and crop bounds
-     * are set to the parent's bounds adjusted for surface insets. This surface is created when
-     * {@link ViewRootImpl#createBoundsSurface(int)} is called.
-     * By parenting to this bounds surface, child surfaces can ensure they do not draw into the
-     * surface inset regions set by the parent window.
+     * Child container layer of {@code mSurface} with the same bounds as its parent, and cropped to
+     * the surface insets. This surface is created only if a client requests it via {@link
+     * #getBoundsLayer()}. By parenting to this bounds surface, child surfaces can ensure they do
+     * not draw into the surface inset regions set by the parent window.
      */
-    public final Surface mBoundsSurface = new Surface();
-    private SurfaceSession mSurfaceSession;
-    private SurfaceControl mBoundsSurfaceControl;
+    private SurfaceControl mBoundsLayer;
+
     private final Transaction mTransaction = new Transaction();
 
     @UnsupportedAppUsage
@@ -1576,65 +1579,76 @@ public final class ViewRootImpl implements ViewParent,
         }
     }
 
-    /**
-     * Creates a surface as a child of {@code mSurface} with the same bounds as its parent and
-     * crop bounds set to the parent's bounds adjusted for surface insets.
-     *
-     * @param zOrderLayer Z order relative to the parent surface.
-     */
-    public void createBoundsSurface(int zOrderLayer) {
-        if (mSurfaceSession == null) {
-            mSurfaceSession = new SurfaceSession();
-        }
-        if (mBoundsSurfaceControl != null && mBoundsSurface.isValid()) {
-            return; // surface control for bounds surface already exists.
+    /** Register callback to be notified when the ViewRootImpl surface changes. */
+    interface SurfaceChangedCallback {
+        void surfaceChangedCallback(SurfaceControl.Transaction transaction);
+    }
+
+    private final ArrayList<SurfaceChangedCallback> mSurfaceChangedCallbacks = new ArrayList<>();
+    void addSurfaceChangedCallback(SurfaceChangedCallback c) {
+        mSurfaceChangedCallbacks.add(c);
+    }
+
+    void removeSurfaceChangedCallback(SurfaceChangedCallback c) {
+        mSurfaceChangedCallbacks.remove(c);
+    }
+
+    private void notifySurfaceChanged(SurfaceControl.Transaction transaction) {
+        for (int i = 0; i < mSurfaceChangedCallbacks.size(); i++) {
+            mSurfaceChangedCallbacks.get(i).surfaceChangedCallback(transaction);
         }
+    }
 
-        mBoundsSurfaceControl = new SurfaceControl.Builder(mSurfaceSession)
+     /**
+     * Returns a child layer with the same bounds as its parent {@code mSurface} and cropped to the
+     * surface insets. If the layer does not exist, it is created.
+     *
+     * <p>Parenting to this layer will ensure that its children are cropped by the view's surface
+     * insets.
+     */
+    public SurfaceControl getBoundsLayer() {
+        if (mBoundsLayer == null) {
+            mBoundsLayer = new SurfaceControl.Builder(mSurfaceSession)
+                .setContainerLayer()
                 .setName("Bounds for - " + getTitle().toString())
                 .setParent(mSurfaceControl)
                 .build();
 
-        setBoundsSurfaceCrop();
-        mTransaction.setLayer(mBoundsSurfaceControl, zOrderLayer)
-                    .show(mBoundsSurfaceControl)
-                    .apply();
-        mBoundsSurface.copyFrom(mBoundsSurfaceControl);
+            setBoundsLayerCrop(mTransaction);
+            mTransaction.show(mBoundsLayer).apply();
+        }
+        return mBoundsLayer;
     }
 
-    private void setBoundsSurfaceCrop() {
+    private void setBoundsLayerCrop(Transaction t) {
         // mWinFrame is already adjusted for surface insets. So offset it and use it as
         // the cropping bounds.
         mTempBoundsRect.set(mWinFrame);
         mTempBoundsRect.offsetTo(mWindowAttributes.surfaceInsets.left,
                 mWindowAttributes.surfaceInsets.top);
-        mTransaction.setWindowCrop(mBoundsSurfaceControl, mTempBoundsRect);
+        t.setWindowCrop(mBoundsLayer, mTempBoundsRect);
     }
 
     /**
-     * Called after window layout to update the bounds surface. If the surface insets have
-     * changed or the surface has resized, update the bounds surface.
+     * Called after window layout to update the bounds surface. If the surface insets have changed
+     * or the surface has resized, update the bounds surface.
      */
-    private void updateBoundsSurface() {
-        if (mBoundsSurfaceControl != null && mSurface.isValid()) {
-            setBoundsSurfaceCrop();
-            mTransaction.deferTransactionUntilSurface(mBoundsSurfaceControl,
+    private void updateBoundsLayer() {
+        if (mBoundsLayer != null) {
+            setBoundsLayerCrop(mTransaction);
+            mTransaction.deferTransactionUntilSurface(mBoundsLayer,
                     mSurface, mSurface.getNextFrameNumber())
                     .apply();
         }
     }
 
     private void destroySurface() {
+        if (mBoundsLayer != null) {
+            mBoundsLayer.release();
+            mBoundsLayer = null;
+        }
         mSurface.release();
         mSurfaceControl.release();
-
-        mSurfaceSession = null;
-
-        if (mBoundsSurfaceControl != null) {
-            mBoundsSurfaceControl.remove();
-            mBoundsSurface.release();
-            mBoundsSurfaceControl = null;
-        }
     }
 
     /**
@@ -2598,7 +2612,7 @@ public final class ViewRootImpl implements ViewParent,
         }
 
         if (surfaceSizeChanged) {
-            updateBoundsSurface();
+            updateBoundsLayer();
         }
 
         final boolean didLayout = layoutRequested && (!mStopped || mReportNextDraw);
@@ -3438,7 +3452,9 @@ public final class ViewRootImpl implements ViewParent,
     private void reportDrawFinished() {
         try {
             mDrawsNeededToReport = 0;
-            mWindowSession.finishDrawing(mWindow);
+            if (mSurfaceControl.isValid()) {
+                mWindowSession.finishDrawing(mWindow, mChangeSurfaceTransaction);
+            }
         } catch (RemoteException e) {
             // Have fun!
         }
@@ -7089,6 +7105,9 @@ public final class ViewRootImpl implements ViewParent,
             frameNumber = mSurface.getNextFrameNumber();
         }
 
+        mPreviousSurfaceControlHandle = mSurfaceControl.isValid()
+                ? mSurfaceControl.getHandle() : null;
+
         int relayoutResult = mWindowSession.relayout(mWindow, mSeq, params,
                 (int) (mView.getMeasuredWidth() * appScale + 0.5f),
                 (int) (mView.getMeasuredHeight() * appScale + 0.5f), viewVisibility,
@@ -7102,6 +7121,11 @@ public final class ViewRootImpl implements ViewParent,
             destroySurface();
         }
 
+        if (mPreviousSurfaceControlHandle != null && mSurfaceControl.isValid()
+                && mPreviousSurfaceControlHandle != mSurfaceControl.getHandle()) {
+            notifySurfaceChanged(mChangeSurfaceTransaction);
+        }
+
         mPendingAlwaysConsumeSystemBars =
                 (relayoutResult & WindowManagerGlobal.RELAYOUT_RES_CONSUME_ALWAYS_SYSTEM_BARS) != 0;
 
@@ -7326,7 +7350,8 @@ public final class ViewRootImpl implements ViewParent,
                         try {
                             if ((relayoutWindow(mWindowAttributes, viewVisibility, false)
                                     & WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) {
-                                mWindowSession.finishDrawing(mWindow);
+                                mWindowSession.finishDrawing(
+                                        mWindow, null /* postDrawTransaction */);
                             }
                         } catch (RemoteException e) {
                         }