Polish for all apps physics.

By adjusting the start value based on the direction of the scroll,
the springs will appear more smooth.

This only changes the appearance of the spring when scrolling down,
since the start value has always been 1 and thus looked fine when
scrolling up.

Bug: 38349031
Change-Id: I563e6e7cfdbc74c4a95adb22f90d5efe17dfa453

src/com/android/launcher3/allapps/AllAppsTransitionController.java

@@ -228,7 +228,8 @@ public class AllAppsTransitionController implements TouchController, VerticalPul
                 }
                 mLauncher.showAppsView(true /* animated */, false /* updatePredictedApps */);
                 if (hasSpringAnimationHandler()) {
-                    mSpringAnimationHandler.animateToFinalPosition(0);
+                    // The icons are moving upwards, so we go to 0 from 1. (y-axis 1 is below 0.)
+                    mSpringAnimationHandler.animateToFinalPosition(0 /* pos */, 1 /* startValue */);
                 }
             } else {
                 calculateDuration(velocity, Math.abs(mShiftRange - mAppsView.getTranslationY()));