Clear recycler view on URL focus clear.

This change ensures that the RecyclerView clears the view pool
when the user ends interaction with the Omnibox.

Bug: 1075602
Change-Id: Iacd36ade19e67144421674cc85c05b750bd0b7b0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2404390
Commit-Queue: Tomasz Wiszkowski <ender@google.com>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805957}

chrome/android/java/src/org/chromium/chrome/browser/omnibox/suggestions/OmniboxSuggestionsDropdown.java

@@ -61,6 +61,9 @@ public interface OmniboxSuggestionsDropdown {
     /** Show (and properly size) the suggestions list. */
     void show();
 
+    /** Hide the suggestions list and release any cached resources. */
+    void hide();
+
     /**
      * Sets the embedder for the list view.
      * @param embedder the embedder of this list.

chrome/android/java/src/org/chromium/chrome/browser/omnibox/suggestions/OmniboxSuggestionsList.java

@@ -87,6 +87,12 @@ public class OmniboxSuggestionsList
         if (getSelectedItemPosition() != 0) setSelection(0);
     }
 
+    @Override
+    public void hide() {
+        if (getVisibility() != VISIBLE) return;
+        setVisibility(GONE);
+    }
+
     @Override
     public void refreshPopupBackground(boolean isIncognito) {
         setBackground(mDropdownDelegate.getPopupBackground(isIncognito));

chrome/android/java/src/org/chromium/chrome/browser/omnibox/suggestions/OmniboxSuggestionsRecyclerView.java

@@ -150,6 +150,13 @@ public class OmniboxSuggestionsRecyclerView
         }
     }
 
+    @Override
+    public void hide() {
+        if (getVisibility() != VISIBLE) return;
+        setVisibility(GONE);
+        getRecycledViewPool().clear();
+    }
+
     @Override
     public void refreshPopupBackground(boolean isIncognito) {
         setBackground(mDropdownDelegate.getPopupBackground(isIncognito));

chrome/android/java/src/org/chromium/chrome/browser/omnibox/suggestions/SuggestionListViewBinder.java

@@ -45,7 +45,7 @@ class SuggestionListViewBinder {
                 if (dropdownView.getParent() == null) view.container.addView(dropdownView);
                 view.dropdown.show();
             } else {
-                dropdownView.setVisibility(View.GONE);
+                view.dropdown.hide();
                 UiUtils.removeViewFromParent(dropdownView);
                 view.container.setVisibility(View.INVISIBLE);
             }