Fix search UI

- Message list is collapsed by default in 7 inch and 10 inch portrait. It can cause confusion when searching.
- We should uncollapse the list in this case.
Bug: 5587501

Change-Id: I2a272e28e1cad7895049c4aa4ee1d8d2918efba9

src/com/android/email/activity/ThreePaneLayout.java

@@ -294,6 +294,9 @@ public class ThreePaneLayout extends LinearLayout implements View.OnClickListene
 
         if (mPaneState == STATE_RIGHT_VISIBLE) {
             return changePaneState(STATE_MIDDLE_EXPANDED, true);
+        } else if (mInitialPaneState == STATE_RIGHT_VISIBLE) {
+            mInitialPaneState = STATE_MIDDLE_EXPANDED;
+            return true;
         }
 
         return false;

src/com/android/email/activity/UIControllerTwoPane.java

@@ -337,6 +337,7 @@ class UIControllerTwoPane extends UIControllerBase implements ThreePaneLayout.Ca
             mThreePane.showRightPane();
         } else if (mListContext.isSearch()) {
             mThreePane.showRightPane();
+            mThreePane.uncollapsePane();
         } else {
             mThreePane.showLeftPane();
         }