[Custom Tabs]Fix a bug that activateContents will pop up a blank chrome

chrome/android/java/src/org/chromium/chrome/browser/tab/ChromeTab.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/ChromeTab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/ChromeTab.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/ChromeTab.java
index 4f7869e8622462011d760637faa087bb43ae4f08..1ac44bd4782835383d470aa0acd679f9a3301351 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/ChromeTab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tab/ChromeTab.java
@@ -420,9 +420,14 @@ public class ChromeTab extends Tab {
             TabModel model = getTabModel();
             int index = model.indexOf(ChromeTab.this);
             if (index == TabModel.INVALID_TAB_INDEX) return;
-
             TabModelUtils.setIndex(model, index);
+            bringActivityToForeground();
+        }
 
+        /**
+         * Brings chrome's Activity to foreground, if it is not so.
+         */
+        protected void bringActivityToForeground() {
             // This intent is sent in order to get the activity back to the foreground if it was
             // not already. The previous call will activate the right tab in the context of the
             // TabModel but will only show the tab to the user if Chrome was already in the