Reland "Add/plumb SurfaceControl.DISPLAY_DECORATION"

The first time this topic landed, it resulted in b/212402133. We avoid
running into this bug with Ib11d46439db57b90486bad07dd90f2cf0822182a.

Original commit message:

When passed to native, this flag will tell a Layer that it should use
Composition.DISPLAY_DECORATION.

Bug: 193170859
Test: manual

Change-Id: I7f1685eb7dc57271f532065dcd1d4dcc449c5cb0

core/java/android/view/SurfaceControl.java

@@ -514,6 +514,15 @@ public final class SurfaceControl implements Parcelable {
      */
     public static final int ENABLE_BACKPRESSURE = 0x00000100;
 
+    /**
+     * Buffers from this SurfaceControl should be considered display decorations.
+     *
+     * If the hardware has optimizations for display decorations (e.g. rounded corners, camera
+     * cutouts, etc), it should use them for this layer.
+     * @hide
+     */
+    public static final int DISPLAY_DECORATION = 0x00000200;
+
     /**
      * Surface creation flag: Creates a surface where color components are interpreted
      * as "non pre-multiplied" by their alpha channel. Of course this flag is
@@ -3265,6 +3274,21 @@ public final class SurfaceControl implements Parcelable {
             return this;
         }
 
+        /**
+         * Sets whether the surface should take advantage of display decoration optimizations.
+         * @hide
+         */
+        public Transaction setDisplayDecoration(SurfaceControl sc, boolean displayDecoration) {
+            checkPreconditions(sc);
+            if (displayDecoration) {
+                nativeSetFlags(mNativeObject, sc.mNativeObject, DISPLAY_DECORATION,
+                        DISPLAY_DECORATION);
+            } else {
+                nativeSetFlags(mNativeObject, sc.mNativeObject, 0, DISPLAY_DECORATION);
+            }
+            return this;
+        }
+
         /**
          * Indicates whether the surface must be considered opaque, even if its pixel format is
          * set to translucent. This can be useful if an application needs full RGBA 8888 support

core/java/android/view/ViewRootImpl.java

@@ -491,6 +491,9 @@ public final class ViewRootImpl implements ViewParent,
     protected final ViewFrameInfo mViewFrameInfo = new ViewFrameInfo();
     private final InputEventAssigner mInputEventAssigner = new InputEventAssigner();
 
+    // Whether to draw this surface as DISPLAY_DECORATION.
+    boolean mDisplayDecorationCached = false;
+
     /**
      * Update the Choreographer's FrameInfo object with the timing information for the current
      * ViewRootImpl instance. Erase the data in the current ViewFrameInfo to prepare for the next
@@ -2842,6 +2845,9 @@ public final class ViewRootImpl implements ViewParent,
                 if (mSurfaceControl.isValid()) {
                     updateOpacity(mWindowAttributes, dragResizing,
                             surfaceControlChanged /*forceUpdate */);
+                    if (surfaceControlChanged) {
+                        updateDisplayDecoration();
+                    }
                 }
 
                 if (DEBUG_LAYOUT) Log.v(mTag, "relayout: frame=" + frame.toShortString()
@@ -10398,6 +10404,23 @@ public final class ViewRootImpl implements ViewParent,
         }
     }
 
+    /**
+     * @hide
+     */
+    public void setDisplayDecoration(boolean displayDecoration) {
+        if (displayDecoration == mDisplayDecorationCached) return;
+
+        mDisplayDecorationCached = displayDecoration;
+
+        if (mSurfaceControl.isValid()) {
+            updateDisplayDecoration();
+        }
+    }
+
+    private void updateDisplayDecoration() {
+        mTransaction.setDisplayDecoration(mSurfaceControl, mDisplayDecorationCached).apply();
+    }
+
     /**
      * Sends a list of blur regions to SurfaceFlinger, tagged with a frame.
      *