Fix minor problems when resizing/maximizing docked window.

When maximizing the transition should originate from visible bounds, so
the first frame matches what is visible to the user. When switching to
the big surface, we only need to increase the layer by one, instead of
having artificially large value. If we use the large value, it will
cause a flicker over system windows.

Also includes some cleanup, like static imports and necessary logging.

Bug: 24913915

Change-Id: I84d7594622aa639e2008c662f941edf9c20b3202
diff --git a/services/core/java/com/android/server/wm/WallpaperController.java b/services/core/java/com/android/server/wm/WallpaperController.java
index 4a9d8cb..3ca4598 100644
--- a/services/core/java/com/android/server/wm/WallpaperController.java
+++ b/services/core/java/com/android/server/wm/WallpaperController.java
@@ -149,11 +149,11 @@
     }
 
     void updateWallpaperVisibility() {
-        final boolean visible = isWallpaperVisible(mWallpaperTarget);
         final DisplayContent displayContent = mWallpaperTarget.getDisplayContent();
         if (displayContent == null) {
             return;
         }
+        final boolean visible = isWallpaperVisible(mWallpaperTarget);
         final DisplayInfo displayInfo = displayContent.getDisplayInfo();
         final int dw = displayInfo.logicalWidth;
         final int dh = displayInfo.logicalHeight;
@@ -205,7 +205,7 @@
                 final WindowState wallpaper = token.windows.get(j);
                 final WindowStateAnimator winAnimator = wallpaper.mWinAnimator;
                 if (!winAnimator.mLastHidden || wasDeferred) {
-                    winAnimator.hide();
+                    winAnimator.hide("hideWallpapers");
                     dispatchWallpaperVisibility(wallpaper, false);
                     final DisplayContent displayContent = wallpaper.getDisplayContent();
                     if (displayContent != null) {