Fix extra offset of the split layout

Use parent based coordinate instead of screen based coordinate when
indicating split surfaces' position so they won't be offset unexpectedly
when its parent is not at (0, 0).

Fix: 210696145
Test: check split UI when enabled "render apps below cutout area"
Change-Id: I65399f5ef2975e7ef376d161c41de2cfb7ed29dc

libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java

@@ -144,21 +144,42 @@ public final class SplitLayout implements DisplayInsetsController.OnInsetsChange
         return Math.max(dividerInset, radius);
     }
 
-    /** Gets bounds of the primary split. */
+    /** Gets bounds of the primary split with screen based coordinate. */
     public Rect getBounds1() {
         return new Rect(mBounds1);
     }
 
-    /** Gets bounds of the secondary split. */
+    /** Gets bounds of the primary split with parent based coordinate. */
+    public Rect getRefBounds1() {
+        Rect outBounds = getBounds1();
+        outBounds.offset(-mRootBounds.left, -mRootBounds.top);
+        return outBounds;
+    }
+
+    /** Gets bounds of the secondary split with screen based coordinate. */
     public Rect getBounds2() {
         return new Rect(mBounds2);
     }
 
-    /** Gets bounds of divider window. */
+    /** Gets bounds of the secondary split with parent based coordinate. */
+    public Rect getRefBounds2() {
+        final Rect outBounds = getBounds2();
+        outBounds.offset(-mRootBounds.left, -mRootBounds.top);
+        return outBounds;
+    }
+
+    /** Gets bounds of divider window with screen based coordinate. */
     public Rect getDividerBounds() {
         return new Rect(mDividerBounds);
     }
 
+    /** Gets bounds of divider window with parent based coordinate. */
+    public Rect getRefDividerBounds() {
+        final Rect outBounds = getDividerBounds();
+        outBounds.offset(-mRootBounds.left, -mRootBounds.top);
+        return outBounds;
+    }
+
     /** Returns leash of the current divider bar. */
     @Nullable
     public SurfaceControl getDividerLeash() {
@@ -452,14 +473,17 @@ public final class SplitLayout implements DisplayInsetsController.OnInsetsChange
             SurfaceControl leash2, SurfaceControl dimLayer1, SurfaceControl dimLayer2) {
         final SurfaceControl dividerLeash = getDividerLeash();
         if (dividerLeash != null) {
-            t.setPosition(dividerLeash, mDividerBounds.left, mDividerBounds.top);
+            mTempRect.set(getRefDividerBounds());
+            t.setPosition(dividerLeash, mTempRect.left, mTempRect.top);
             // Resets layer of divider bar to make sure it is always on top.
             t.setLayer(dividerLeash, SPLIT_DIVIDER_LAYER);
         }
-        t.setPosition(leash1, mBounds1.left, mBounds1.top)
-                .setWindowCrop(leash1, mBounds1.width(), mBounds1.height());
-        t.setPosition(leash2, mBounds2.left, mBounds2.top)
-                .setWindowCrop(leash2, mBounds2.width(), mBounds2.height());
+        mTempRect.set(getRefBounds1());
+        t.setPosition(leash1, mTempRect.left, mTempRect.top)
+                .setWindowCrop(leash1, mTempRect.width(), mTempRect.height());
+        mTempRect.set(getRefBounds2());
+        t.setPosition(leash2, mTempRect.left, mTempRect.top)
+                .setWindowCrop(leash2, mTempRect.width(), mTempRect.height());
 
         if (mImePositionProcessor.adjustSurfaceLayoutForIme(
                 t, dividerLeash, leash1, leash2, dimLayer1, dimLayer2)) {

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java

@@ -979,7 +979,8 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
             t.setAlpha(dividerLeash, 1);
             t.setLayer(dividerLeash, SPLIT_DIVIDER_LAYER);
             t.setPosition(dividerLeash,
-                    mSplitLayout.getDividerBounds().left, mSplitLayout.getDividerBounds().top);
+                    mSplitLayout.getRefDividerBounds().left,
+                    mSplitLayout.getRefDividerBounds().top);
         } else {
             t.hide(dividerLeash);
         }

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/splitscreen/SplitTestUtils.java

@@ -18,6 +18,7 @@ package com.android.wm.shell.splitscreen;
 
 import static android.view.Display.DEFAULT_DISPLAY;
 import static android.window.DisplayAreaOrganizer.FEATURE_DEFAULT_TASK_CONTAINER;
+
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 
@@ -51,6 +52,7 @@ public class SplitTestUtils {
         final SurfaceControl leash = createMockSurface();
         SplitLayout out = mock(SplitLayout.class);
         doReturn(dividerBounds).when(out).getDividerBounds();
+        doReturn(dividerBounds).when(out).getRefDividerBounds();
         doReturn(leash).when(out).getDividerLeash();
         return out;
     }