Never show the omnibox shadow if showing on GTS.

R=yusufo@chromium.org

Bug: 970585
Change-Id: I790264b9fab0e7d88da12c737405130d6dd9f28f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1647960
Commit-Queue: Matt Simmons <mattsimmons@chromium.org>
Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667174}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/top/ToolbarPhone.java

@@ -2347,7 +2347,9 @@ public class ToolbarPhone extends ToolbarLayout implements Invalidator.Client, O
         // TODO(twellington): Move this shadow state information to ToolbarDataProvider and show
         // shadow when incognito NTP is scrolled.
         return mTabSwitcherState == STATIC_TAB && !hideShadowForIncognitoNtp()
-                && !hideShadowForInterstitial();
+                && !hideShadowForInterstitial()
+                && (getToolbarDataProvider() != null
+                        && !getToolbarDataProvider().isInOverviewAndShowingOmnibox());
     }
 
     private boolean hideShadowForIncognitoNtp() {