Fix crash when showing multiple popups.

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index d0551617f22b17a39b8370e4a628ef3414a8fa31..a7fcdadfa678acab657534d83db30de0912e3447 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -2171,12 +2171,14 @@ public class ContentViewCore
             return;
         }
 
+        hidePopupsAndClearSelection();
+        assert mNativeSelectPopupSourceFrame == 0 : "Zombie popup did not clear the frame source";
+
         assert items.length == enabled.length;
         List<SelectPopupItem> popupItems = new ArrayList<SelectPopupItem>();
         for (int i = 0; i < items.length; i++) {
             popupItems.add(new SelectPopupItem(items[i], enabled[i]));
         }
-        hidePopupsAndClearSelection();
         if (DeviceFormFactor.isTablet(mContext) && !multiple) {
             mSelectPopup = new SelectPopupDropdown(this, popupItems, bounds, selectedIndices);
         } else {