Fix contextual search peeking pari is hidden behind CCT bottom bar

When CCT bottom bar is shown, the contextual search peeking bar is hidden
beneath it. The correct behavior should be when contextual search bar is
shown, CCT bottom bar should be dismissed.

To fix the problem, add a ContextualSearchObserver from the
CustomTabBottomBarDelegate to know when the contextual search bar is
shown/hidden, then hide/show bottom bar based on the observer's
callbacks.

BUG=684675

Change-Id: Iad53e7b8e83afcf127c7adcf1965cd4f75bc0afa
Reviewed-on: https://chromium-review.googlesource.com/693343Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Commit-Queue: Lei Tian <ltian@google.com>
Cr-Commit-Position: refs/heads/master@{#505887}

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java

@@ -620,6 +620,7 @@ public class CustomTabActivity extends ChromeActivity {
     public void initializeCompositor() {
         super.initializeCompositor();
         getTabModelSelector().onNativeLibraryReady(getTabContentManager());
+        mBottomBarDelegate.addContextualSearchObserver();
     }
 
     private void recordClientPackageName() {

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabBottomBarDelegate.java

@@ -8,6 +8,7 @@ import android.app.PendingIntent;
 import android.app.PendingIntent.CanceledException;
 import android.content.Intent;
 import android.net.Uri;
+import android.support.annotation.Nullable;
 import android.support.customtabs.CustomTabsIntent;
 import android.view.View;
 import android.view.View.OnClickListener;
@@ -22,8 +23,11 @@ import org.chromium.base.Log;
 import org.chromium.base.metrics.CachedMetrics;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.browser.contextualsearch.ContextualSearchManager;
+import org.chromium.chrome.browser.contextualsearch.ContextualSearchObserver;
 import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager;
 import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager.FullscreenListener;
+import org.chromium.chrome.browser.gsa.GSAContextDisplaySelection;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.ui.interpolators.BakedBezierInterpolator;
 
@@ -159,6 +163,34 @@ class CustomTabBottomBarDelegate implements FullscreenListener {
         return mBottomBarView;
     }
 
+    public void addContextualSearchObserver() {
+        ContextualSearchManager manager = mActivity.getContextualSearchManager();
+        if (manager != null) {
+            ContextualSearchObserver observer = new ContextualSearchObserver() {
+                @Override
+                public void onShowContextualSearch(
+                        @Nullable GSAContextDisplaySelection selectionContext) {
+                    getBottomBarView()
+                            .animate()
+                            .alpha(0)
+                            .setInterpolator(BakedBezierInterpolator.TRANSFORM_CURVE)
+                            .setDuration(SLIDE_ANIMATION_DURATION_MS)
+                            .start();
+                }
+                @Override
+                public void onHideContextualSearch() {
+                    getBottomBarView()
+                            .animate()
+                            .alpha(1)
+                            .setInterpolator(BakedBezierInterpolator.TRANSFORM_CURVE)
+                            .setDuration(SLIDE_ANIMATION_DURATION_MS)
+                            .start();
+                }
+            };
+            manager.addObserver(observer);
+        }
+    }
+
     private void hideBottomBar() {
         if (mBottomBarView == null) return;
         mBottomBarView.animate().alpha(0f).translationY(mBottomBarView.getHeight())