Use View Holder pattern in AccountsAdapter.getView().

Currently, the lint warns at:
AccountsAdapter.java:29 Unconditional layout inflation from view adapter:
    Should use View Holder pattern (use recycled view passed into this method
    as the second parameter) for smoother scrolling: ViewHolder [warning]

This CL fixes the above lint error.

BUG=327768

Review URL: https://codereview.chromium.org/628133003

Cr-Commit-Position: refs/heads/master@{#299406}

remoting/android/java/src/org/chromium/chromoting/AccountsAdapter.java

@@ -26,7 +26,10 @@ public class AccountsAdapter extends ArrayAdapter<Account> {
 
     @Override
     public View getView(int position, View convertView, ViewGroup parent) {
-        View view = mInflater.inflate(R.layout.account_selected, parent, false);
+        View view = convertView;
+        if (view == null) {
+            view = mInflater.inflate(R.layout.account_selected, parent, false);
+        }
         Account account = getItem(position);
         TextView target = (TextView) view.findViewById(R.id.account_name);
         target.setText(account.name);