use SkStream factory for files, and check for null (file-not-found) speedup sampleapp's animation

samplecode/SampleApp.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SampleApp.h"
 
 #include "SkData.h"
 #include "SkCanvas.h"
@@ skipping 56 matching lines @@
 
 #define USE_ARROWS_FOR_ZOOM true
 
 #if SK_ANGLE
 //#define DEFAULT_TO_ANGLE 1
 #else
 //#define DEFAULT_TO_GPU 1
 #endif
 
 #define ANIMATING_EVENTTYPE "nextSample"
-#define ANIMATING_DELAY     750
+#define ANIMATING_DELAY     250
 
 #ifdef SK_DEBUG
     #define FPS_REPEAT_MULTIPLIER   1
 #else
     #define FPS_REPEAT_MULTIPLIER   10
 #endif
 #define FPS_REPEAT_COUNT    (10 * FPS_REPEAT_MULTIPLIER)
 
 static SampleWindow* gSampleWindow;
 
@@ skipping 2367 matching lines @@
     SkGraphics::Init();
     SkEvent::Init();
 }
 
 // FIXME: this should be in a header
 void application_term();
 void application_term() {
     SkEvent::Term();
     SkGraphics::Term();
 }