[Android] Default allow infobars to hide on scroll.

Accidentally disabled in:
https://codereview.chromium.org/968453002

BUG=452614

Review URL: https://codereview.chromium.org/989783002

Cr-Commit-Position: refs/heads/master@{#319640}

chrome/android/java/src/org/chromium/chrome/browser/infobar/InfoBarContainer.java

@@ -41,7 +41,7 @@ public class InfoBarContainer extends SwipableOverlayView {
     private static final int TAB_STRIP_AND_TOOLBAR_HEIGHT_TABLET_DP = 96;
 
     /** WHether or not the InfoBarContainer is allowed to hide when the user scrolls. */
-    private static boolean sIsAllowedToAutoHide;
+    private static boolean sIsAllowedToAutoHide = true;
 
     /**
      * A listener for the InfoBar animation.