More accurate render time and continuous fresh

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;
 
-static double now_ms() { return SkTime::GetNSecs() * 1e-6; }
-
 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);
 
-    double currentTime = 0.0;
-    double previousTime = 0.0;
-
     // Get the file descriptor for the X display
     int x11_fd = ConnectionNumber(display);
     fd_set in_fds;
 
     SkTHashSet<sk_app::Window_unix*> pendingWindows;
     bool done = false;
     while (!done) {
         // Create a file description set containing x11_fd
         FD_ZERO(&in_fds);
         FD_SET(x11_fd, &in_fds);
@@ skipping 26 matching lines @@
             default:
                 if (win->handleEvent(event)) {
                     done = true;
                 }
                 break;
             } 
         }
         
         pendingWindows.foreach(finishWindow);
         if (pendingWindows.count() > 0) {
-            previousTime = currentTime;
-            currentTime = now_ms();
-            app->onIdle(currentTime - previousTime);        
+            app->onIdle();
         }
         pendingWindows.reset();
     }
 
     delete app;
 
     XCloseDisplay(display);
 
     return 0;
 }