Clean up Xlib viewer

tools/viewer/sk_app/unix/main_unix.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "SkTypes.h"
 #include "SkTHash.h"
 #include "Timer.h"
 #include "Window_unix.h"
 #include "../Application.h"
 
 using sk_app::Application;
 
 void finishWindow(sk_app::Window_unix* win) {
     win->finishResize();
     win->finishPaint();
 }
 
 int main(int argc, char**argv) {
 
     Display* display = XOpenDisplay(nullptr);
 
     Application* app = Application::Create(argc, argv, (void*)display);
 
     // Get the file descriptor for the X display
     int x11_fd = ConnectionNumber(display);
-    fd_set in_fds;
+    int count = x11_fd + 1;
 
     SkTHashSet<sk_app::Window_unix*> pendingWindows;
     bool done = false;
     while (!done) {
         // Create a file description set containing x11_fd
+        fd_set in_fds;
         FD_ZERO(&in_fds);
         FD_SET(x11_fd, &in_fds);
 
         // Set a sleep timer
         struct timeval tv;
         tv.tv_usec = 100;
         tv.tv_sec = 0;
 
-        // Wait for an event on the file descriptor or for timer expiration
-        (void) select(1, &in_fds, NULL, NULL, &tv);
+        while (!XPending(display)) {
+            // Wait for an event on the file descriptor or for timer expiration
+            (void) select(count, &in_fds, NULL, NULL, &tv);
+        }
 
         // Handle XEvents (if any) and flush the input 
-        XEvent event;
-        while (XPending(display) && !done) {
+        int count = XPending(display);
+        while (count-- && !done) {
+            XEvent event;
             XNextEvent(display, &event);
 
             sk_app::Window_unix* win = sk_app::Window_unix::gWindowMap.find(event.xany.window);
             // paint and resize events get collapsed
             switch (event.type) {
             case Expose: 
                 win->markPendingPaint();
                 pendingWindows.add(win);
                 break;
             case ConfigureNotify:
                 win->markPendingResize(event.xconfigurerequest.width,
                                        event.xconfigurerequest.height);
                 pendingWindows.add(win);
                 break;
             default:
                 if (win->handleEvent(event)) {
                     done = true;
                 }
                 break;
             } 
         }
         
         pendingWindows.foreach(finishWindow);
         if (pendingWindows.count() > 0) {
             app->onIdle();
         }
         pendingWindows.reset();
+
+        XFlush(display);
     }
 
     delete app;
 
     XCloseDisplay(display);
 
     return 0;
 }