Revert "Update tab switcher state in ToolbarPhone after animation completes"

This reverts commit 99c1a2c3.

Reason for revert: Causes bugs 820349 & 816858

Original change's description:
> Update tab switcher state in ToolbarPhone after animation completes
> 
> Previously onTabSwitcherTransitionFinished was only called when
> exiting the tab switcher. This change implements
> onOverviewModeFinishedShowing to call this method.
> 
> BUG=710750
> 
> Change-Id: I1a34551a6cd93a54a9461441c25ce022144efa9e
> Reviewed-on: https://chromium-review.googlesource.com/929991
> Reviewed-by: David Trainor <dtrainor@chromium.org>
> Reviewed-by: Ted Choc <tedchoc@chromium.org>
> Commit-Queue: Matthew Jones <mdjones@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#539205}

TBR=dtrainor@chromium.org,tedchoc@chromium.org,mdjones@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 710750
Change-Id: Ia5dd268f289f1fbb5bb0e0614c6242ec905a4ecc
Reviewed-on: https://chromium-review.googlesource.com/956937Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542143}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java

@@ -584,11 +584,6 @@ public class ToolbarManager implements ToolbarTabController, UrlFocusChangeListe
             public void onOverviewModeFinishedHiding() {
                 mToolbar.onTabSwitcherTransitionFinished();
             }
-
-            @Override
-            public void onOverviewModeFinishedShowing() {
-                mToolbar.onTabSwitcherTransitionFinished();
-            }
         };
 
         mSceneChangeObserver = new SceneChangeObserver() {