Various OpenGLUI changes:

runtime/embedders/openglui/common/graphics_handler.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "embedders/openglui/common/graphics_handler.h"
 #include "embedders/openglui/common/canvas_context.h"
 #include "embedders/openglui/common/log.h"
 
 extern void CheckGLError(const char *function);
 
@@ skipping 91 matching lines @@
 }
 
 void GraphicsHandler::SetViewport(int left, int top, int width, int height) {
   width_ = width;
   height_ = height;
   glViewport(left, top, width, height);
   CheckGLError("glViewPort");
 }
 
 int32_t GraphicsHandler::Update() {
+  LOGI("In GraphicsHandler::Update, display_context dirty %s",
+    (display_context == NULL ? "NULL" :
+        (display_context->isDirty() ? "yes":"no")));
   if (display_context != NULL && display_context->isDirty()) {
     LOGI("Flushing display context\n");
     display_context->Flush();
     SwapBuffers();
     display_context->clearDirty();
   }
   return 0;
 }