Refactor to convert four state booleans to int.

Replace four booleans (mDrawPending, mCommitDrawPending, mReadyToShow
and mHasDrawn) with a single int that can take on the four states.

Move mLastHidden from WindowState to WindowStateAnimator.

Change-Id: Ieff319dfa19123bf5a6cdc98e9ab28fd432b8153
diff --git a/services/java/com/android/server/wm/AppWindowToken.java b/services/java/com/android/server/wm/AppWindowToken.java
index 09e99a5..3069b74 100644
--- a/services/java/com/android/server/wm/AppWindowToken.java
+++ b/services/java/com/android/server/wm/AppWindowToken.java
@@ -394,8 +394,7 @@
                 if (!win.isDrawnLw()) {
                     Slog.v(WindowManagerService.TAG, "Not displayed: s=" + win.mWinAnimator.mSurface
                             + " pv=" + win.mPolicyVisibility
-                            + " dp=" + win.mWinAnimator.mDrawPending
-                            + " cdp=" + win.mWinAnimator.mCommitDrawPending
+                            + " mDrawState=" + win.mWinAnimator.mDrawState
                             + " ah=" + win.mAttachedHidden
                             + " th="
                             + (win.mAppToken != null