Fix black screen issue while closing tabs.

Add check for corner case while scheduling remove tab where
tab to remove is not same as active tab.

Change-Id: I3b29023c10c2a3821f36a43e465df27d663c0811
diff --git a/src/com/android/browser/BaseUi.java b/src/com/android/browser/BaseUi.java
index b0f9129..da9ad63 100644
--- a/src/com/android/browser/BaseUi.java
+++ b/src/com/android/browser/BaseUi.java
@@ -326,6 +326,17 @@
     Runnable mRunnable = null;
 
     protected void scheduleRemoveTab(Tab tabToRemove, Tab tabToWaitFor) {
+
+        if(tabToWaitFor == mTabToRemove) {
+            if (mRunnable != null) {
+                mTitleBar.removeCallbacks(mRunnable);
+            }
+            mTabToRemove = null;
+            mTabToWaitFor = null;
+            mRunnable = null;
+            return;
+        }
+
         //remove previously scehduled tab
         if (mTabToRemove != null) {
             if (mRunnable != null)