DisplayManager: Add an API to query for DISPLAY_DECORATON

Tunnel through SurfaceControl to determine whether the HWC has this
capability. This allows clients (i.e. SystemUI) to know whether they can
use Composition.DISPLAY_DECORATON. If so, they may want to render
differently (i.e. in A8). See Ib948c38ee189877eda675a6342cb70099f66122b
for an example.

Bug: 193170859
Test: manual
Test: TODO
Change-Id: I9904452b6408199bb1f86de9e21132e4d4444e1a

core/java/android/hardware/display/DisplayManager.java

@@ -1205,6 +1205,17 @@ public final class DisplayManager {
         mGlobal.setRefreshRateSwitchingType(newValue);
     }
 
+    /**
+     * Returns whether the specified display supports DISPLAY_DECORATION.
+     *
+     * @param displayId The display to query support.
+     *
+     * @hide
+     */
+    public boolean getDisplayDecorationSupport(int displayId) {
+        return mGlobal.getDisplayDecorationSupport(displayId);
+    }
+
     /**
      * Returns the user preference for "Match content frame rate".
      * <p>

core/java/android/hardware/display/DisplayManagerGlobal.java

@@ -811,6 +811,21 @@ public final class DisplayManagerGlobal {
         }
     }
 
+    /**
+     * Report whether the display supports DISPLAY_DECORATION.
+     *
+     * @param displayId The display whose support is being queried.
+     *
+     * @hide
+     */
+    public boolean getDisplayDecorationSupport(int displayId) {
+        try {
+            return mDm.getDisplayDecorationSupport(displayId);
+        } catch (RemoteException ex) {
+            throw ex.rethrowFromSystemServer();
+        }
+    }
+
     /**
      * Gets the brightness of the display.
      *

core/java/android/hardware/display/IDisplayManager.aidl

@@ -180,4 +180,7 @@ interface IDisplayManager {
 
     // Returns the refresh rate switching type.
     int getRefreshRateSwitchingType();
+
+    // Query for DISPLAY_DECORATION support.
+    boolean getDisplayDecorationSupport(int displayId);
 }

core/java/android/view/SurfaceControl.java

@@ -231,6 +231,7 @@ public final class SurfaceControl implements Parcelable {
             float shadowRadius);
     private static native void nativeSetGlobalShadowSettings(@Size(4) float[] ambientColor,
             @Size(4) float[] spotColor, float lightPosY, float lightPosZ, float lightRadius);
+    private static native boolean nativeGetDisplayDecorationSupport(IBinder displayToken);
 
     private static native void nativeSetFrameRate(long transactionObj, long nativeObject,
             float frameRate, int compatibility, int changeFrameRateStrategy);
@@ -2650,6 +2651,20 @@ public final class SurfaceControl implements Parcelable {
         nativeSetGlobalShadowSettings(ambientColor, spotColor, lightPosY, lightPosZ, lightRadius);
     }
 
+    /**
+     * Returns whether a display supports DISPLAY_DECORATION.
+     *
+     * @param displayToken
+     *      The token for the display.
+     *
+     * @return Whether the display supports DISPLAY_DECORATION.
+     *
+     * @hide
+     */
+    public static boolean getDisplayDecorationSupport(IBinder displayToken) {
+        return nativeGetDisplayDecorationSupport(displayToken);
+    }
+
     /**
      * Adds a callback to be informed about SF's jank classification for a specific surface.
      * @hide

core/jni/android_view_SurfaceControl.cpp

@@ -1768,6 +1768,15 @@ static void nativeSetGlobalShadowSettings(JNIEnv* env, jclass clazz, jfloatArray
     client->setGlobalShadowSettings(ambientColor, spotColor, lightPosY, lightPosZ, lightRadius);
 }
 
+static jboolean nativeGetDisplayDecorationSupport(JNIEnv* env, jclass clazz,
+        jobject displayTokenObject) {
+    sp<IBinder> displayToken(ibinderForJavaObject(env, displayTokenObject));
+    if (displayToken == nullptr) {
+        return JNI_FALSE;
+    }
+    return static_cast<jboolean>(SurfaceComposerClient::getDisplayDecorationSupport(displayToken));
+}
+
 static jlong nativeGetHandle(JNIEnv* env, jclass clazz, jlong nativeObject) {
     SurfaceControl *surfaceControl = reinterpret_cast<SurfaceControl*>(nativeObject);
     return reinterpret_cast<jlong>(surfaceControl->getHandle().get());
@@ -2092,6 +2101,8 @@ static const JNINativeMethod sSurfaceControlMethods[] = {
             (void*)nativeMirrorSurface },
     {"nativeSetGlobalShadowSettings", "([F[FFFF)V",
             (void*)nativeSetGlobalShadowSettings },
+    {"nativeGetDisplayDecorationSupport", "(Landroid/os/IBinder;)Z",
+            (void*)nativeGetDisplayDecorationSupport},
     {"nativeGetHandle", "(J)J",
             (void*)nativeGetHandle },
     {"nativeSetFixedTransformHint", "(JJI)V",

services/core/java/com/android/server/display/DisplayManagerService.java

@@ -1782,6 +1782,14 @@ public final class DisplayManagerService extends SystemService {
         return mDisplayModeDirector.getModeSwitchingType();
     }
 
+    private boolean getDisplayDecorationSupportInternal(int displayId) {
+        final IBinder displayToken = getDisplayToken(displayId);
+        if (null == displayToken) {
+            return false;
+        }
+        return SurfaceControl.getDisplayDecorationSupport(displayToken);
+    }
+
     private void setBrightnessConfigurationForDisplayInternal(
             @Nullable BrightnessConfiguration c, String uniqueId, @UserIdInt int userId,
             String packageName) {
@@ -3442,6 +3450,16 @@ public final class DisplayManagerService extends SystemService {
                 Binder.restoreCallingIdentity(token);
             }
         }
+
+        @Override // Binder call
+        public boolean getDisplayDecorationSupport(int displayId) {
+            final long token = Binder.clearCallingIdentity();
+            try {
+                return getDisplayDecorationSupportInternal(displayId);
+            } finally {
+                Binder.restoreCallingIdentity(token);
+            }
+        }
     }
 
     private static boolean isValidBrightness(float brightness) {