Sketch splitting SkPicture into an interface and SkBigPicture.

tests/GpuLayerCacheTest.cpp

 /*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #if SK_SUPPORT_GPU
 
 #include "GrContext.h"
@@ skipping 93 matching lines @@
             continue;
         }
 
         GrContext* context = factory->get(glCtxType);
 
         if (NULL == context) {
             continue;
         }
 
         SkPictureRecorder recorder;
-        recorder.beginRecording(1, 1);
+        SkCanvas* c = recorder.beginRecording(1, 1);
+            // Draw something, anything, to prevent an empty-picture optimization,
+            // which is a singleton and never purged.
+            c->drawRect(SkRect::MakeWH(1,1), SkPaint());
         SkAutoTUnref<const SkPicture> picture(recorder.endRecording());
 
         GrLayerCache cache(context);
 
         create_layers(reporter, &cache, *picture, kInitialNumLayers, 0);
 
         for (unsigned i = 0; i < kInitialNumLayers; ++i) {
             unsigned indices[1] = { i + 1 };
             GrCachedLayer* layer = TestingAccess::Find(&cache, picture->uniqueID(), SkMatrix::I(),
                                                        indices, 1);
@@ skipping 116 matching lines @@
 
         picture.reset(NULL);
         cache.processDeletedPictures();
 
         REPORTER_ASSERT(reporter, TestingAccess::NumLayers(&cache) == 0);
         // TODO: add VRAM/resource cache check here
     }
 }
 
 #endif