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

BUG=

Review URL: https://codereview.chromium.org/16173003

git-svn-id: http://skia.googlecode.com/svn/trunk@9327 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 40c9d1f..c5910ef 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -74,7 +74,7 @@
 #endif
 
 #define ANIMATING_EVENTTYPE "nextSample"
-#define ANIMATING_DELAY     750
+#define ANIMATING_DELAY     250
 
 #ifdef SK_DEBUG
     #define FPS_REPEAT_MULTIPLIER   1
diff --git a/samplecode/SamplePicture.cpp b/samplecode/SamplePicture.cpp
index eaec829..825e561 100644
--- a/samplecode/SamplePicture.cpp
+++ b/samplecode/SamplePicture.cpp
@@ -33,14 +33,16 @@
 #include "SkImageRef_GlobalPool.h"
 
 static SkBitmap load_bitmap() {
-    SkStream* stream = new SkFILEStream("/skimages/sesame_street_ensemble-hp.jpg");
-    SkAutoUnref aur(stream);
-
     SkBitmap bm;
-    if (SkImageDecoder::DecodeStream(stream, &bm, SkBitmap::kNo_Config,
-                                     SkImageDecoder::kDecodeBounds_Mode)) {
-        SkPixelRef* pr = new SkImageRef_GlobalPool(stream, bm.config(), 1);
-        bm.setPixelRef(pr)->unref();
+    SkStream* stream = SkStream::NewFromFile("/skimages/sesame_street_ensemble-hp.jpg");
+    if (stream) {
+        SkAutoUnref aur(stream);
+
+        if (SkImageDecoder::DecodeStream(stream, &bm, SkBitmap::kNo_Config,
+                                         SkImageDecoder::kDecodeBounds_Mode)) {
+            SkPixelRef* pr = new SkImageRef_GlobalPool(stream, bm.config(), 1);
+            bm.setPixelRef(pr)->unref();
+        }
     }
     return bm;
 }