Reset Divider IME state when leaving split-screen

This is basically a broad-stroke reset after leaving
split-screen to clean-up ime state inconsistencies. Generally
this won't really do anything, but it should hopefully
prevent bad state from persisting when it does happen.

Bug: 161155771
Test: Use split-screen stuff. It should continue working.
Change-Id: If225dee39b8eca160a32a0953d23ebe86cceff9e

packages/SystemUI/src/com/android/systemui/stackdivider/Divider.java

@@ -529,6 +529,7 @@ public class Divider extends SystemUI implements DividerView.DividerCallbacks,
         updateVisibility(false /* visible */);
         mMinimized = false;
         removeDivider();
+        mImePositionProcessor.reset();
     }
 
     void ensureMinimizedSplit() {

packages/SystemUI/src/com/android/systemui/stackdivider/DividerImeController.java

@@ -117,6 +117,18 @@ class DividerImeController implements DisplayImeController.ImePositionProcessor
                 && (imeSplit.asBinder() == mSplits.mSecondary.token.asBinder());
     }
 
+    void reset() {
+        mPaused = true;
+        mPausedTargetAdjusted = false;
+        mAdjustedWhileHidden = false;
+        mAnimation = null;
+        mAdjusted = mTargetAdjusted = false;
+        mImeWasShown = mTargetShown = false;
+        mTargetPrimaryDim = mTargetSecondaryDim = mLastPrimaryDim = mLastSecondaryDim = 0.f;
+        mSecondaryHasFocus = false;
+        mLastAdjustTop = -1;
+    }
+
     private void updateDimTargets() {
         final boolean splitIsVisible = !getView().isHidden();
         mTargetPrimaryDim = (mSecondaryHasFocus && mTargetShown && splitIsVisible)