Dismiss IME when entering NavScreen.

Change-Id: Id2695cfed20d814385f29f7adda48b0e1b786d84
diff --git a/src/com/android/browser/PhoneUi.java b/src/com/android/browser/PhoneUi.java
index 898acf5..900abff 100644
--- a/src/com/android/browser/PhoneUi.java
+++ b/src/com/android/browser/PhoneUi.java
@@ -267,6 +267,7 @@
 
     void showNavScreen() {
         mShowNav = true;
+        dismissIME();
         mUiController.setBlockEvents(true);
         if (mNavScreen == null) {
             mNavScreen = new NavScreen(mActivity, mUiController, this);