Prevent scrim showing without params

This patch prevents the location bar from attempting to show the scrim
before the view it is supposed to appear behind is inflated (thus
making the params null).

Bug: 856225
Change-Id: I7fabcd421251602cc25132db71fbb0482312458f
Reviewed-on: https://chromium-review.googlesource.com/1113953Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570112}

chrome/android/java/src/org/chromium/chrome/browser/omnibox/LocationBarLayout.java

@@ -2033,7 +2033,7 @@ public class LocationBarLayout extends FrameLayout
      *                        scrim.
      */
     protected void updateFadingBackgroundView(boolean visible, boolean ignoreNtpChecks) {
-        if (mScrim == null) return;
+        if (mScrim == null || mScrimParams == null) return;
         NewTabPage ntp = mToolbarDataProvider.getNewTabPageForCurrentTab();
         boolean locationBarShownInNTP = ntp != null && ntp.isLocationBarShownInNTP();