Avoid extraneous calls to the UI thread

* java/org/gnu/emacs/EmacsView.java (EmacsView)
(showOnScreenKeyboard, hideOnScreenKeyboard)
(onCheckIsTextEditor): Make synchronized.
* java/org/gnu/emacs/EmacsWindow.java (EmacsWindow)
(toggleOnScreenKeyboard): Don't post to the main thread.

java/org/gnu/emacs/EmacsView.java

@@ -590,7 +590,7 @@ else if (child.getVisibility () != GONE)
     super.onAttachedToWindow ();
   }
 
-  public void
+  public synchronized void
   showOnScreenKeyboard ()
   {
     /* Specifying no flags at all tells the system the user asked for
@@ -599,7 +599,7 @@ else if (child.getVisibility () != GONE)
     isCurrentlyTextEditor = true;
   }
 
-  public void
+  public synchronized void
   hideOnScreenKeyboard ()
   {
     imManager.hideSoftInputFromWindow (this.getWindowToken (),
@@ -686,7 +686,7 @@ else if (child.getVisibility () != GONE)
   }
 
   @Override
-  public boolean
+  public synchronized boolean
   onCheckIsTextEditor ()
   {
     /* If value is true, then the system will display the on screen

java/org/gnu/emacs/EmacsWindow.java

@@ -1201,19 +1201,16 @@ else if (EmacsWindow.this.isMapped)
   }
 
   public void
-  toggleOnScreenKeyboard (final boolean on)
+  toggleOnScreenKeyboard (boolean on)
   {
-    EmacsService.SERVICE.runOnUiThread (new Runnable () {
-	@Override
-	public void
-	run ()
-	{
-	  if (on)
-	    view.showOnScreenKeyboard ();
-	  else
-	    view.hideOnScreenKeyboard ();
-	}
-      });
+    /* InputMethodManager functions are thread safe.  Call
+       `showOnScreenKeyboard' etc from the Emacs thread in order to
+       keep the calls in sync with updates to the input context.  */
+
+    if (on)
+      view.showOnScreenKeyboard ();
+    else
+      view.hideOnScreenKeyboard ();
   }
 
   public String