Fix captureTaskBitmap for tasks not positioned at top-left of screen.

Bug: 221442494
Test: Manual testing
Change-Id: I4c570d7f62293f22b60b981120888e9638a14654

services/core/java/com/android/server/wm/WindowManagerService.java

@@ -3920,7 +3920,13 @@ public class WindowManagerService extends IWindowManager.Stub
                 return null;
             }
 
+            // The bounds returned by the task represent the task's position on the screen. However,
+            // we need to specify a crop relative to the task's surface control. Therefore, shift
+            // the task's bounds to 0,0 so that we have the correct size and position within the
+            // task's surface control.
             task.getBounds(mTmpRect);
+            mTmpRect.offsetTo(0, 0);
+
             final SurfaceControl sc = task.getSurfaceControl();
             final SurfaceControl.ScreenshotHardwareBuffer buffer = SurfaceControl.captureLayers(
                     layerCaptureArgsBuilder.setLayer(sc).setSourceCrop(mTmpRect).build());