Revert "use deltas so they don't compound error from mouse offset, #367"

This reverts commit fb5af23.

js/common/model/Mass.ts

@@ -532,13 +532,6 @@ export default abstract class Mass extends PhetioObject {
     this.engine.updatePointerConstraint( this.body, position );
   }
 
-  /**
-   * Updates a current drag with a new 2d (x,y) model delta.
-   */
-  public updateDragFromDelta( delta: Vector2 ): void {
-    this.engine.updatePointerConstraintFromDelta( this.body, delta );
-  }
-
   /**
    * Ends a physics model engine drag.
    */

js/common/model/PhysicsEngine.ts

@@ -401,25 +401,6 @@ export default class PhysicsEngine {
     pointerConstraint.bodyB.wakeUp();
   }
 
-  /**
-   * Updates a pointer constraint so that the body will move by the provided delta value. This can be useful because
-   * pointerConstraints can be initialized with an offset from, the body origin.
-   */
-  public updatePointerConstraintFromDelta( body: PhysicsEngineBody, deltaVector: Vector2 ): void {
-    const delta = PhysicsEngine.vectorToP2( deltaVector );
-
-    const pointerConstraint = this.pointerConstraintMap[ body.id ];
-    assert && assert( pointerConstraint, `pointer constraint expected for physics body #${body.id}` );
-
-    // @ts-expect-error it should have pivotA...
-    pointerConstraint.pivotA[ 0 ] += delta[ 0 ];
-    // @ts-expect-error it should have pivotA...
-    pointerConstraint.pivotA[ 1 ] += delta[ 1 ];
-
-    pointerConstraint.bodyA.wakeUp();
-    pointerConstraint.bodyB.wakeUp();
-  }
-
   /**
    * Removes a pointer constraint.
    */

js/common/view/MassView.ts

@@ -138,7 +138,7 @@ export default abstract class MassView extends Disposable {
         transform: INVERT_Y_TRANSFORM,
         drag: ( event, listener ) => {
           mass.grabDragUsageTracker.shouldShowDragCue = false;
-          mass.updateDragFromDelta( listener.modelDelta ); // Update based on deltas instead of absolute, fixing, https://github.com/phetsims/density-buoyancy-common/issues/367
+          mass.updateDrag( mass.matrix.translation.add( listener.modelDelta ) );
         },
         tandem: Tandem.OPT_OUT
       } );