Add a flag to flush the canvases during SkMultiPictureDraw::draw().

src/core/SkMultiPictureDraw.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.
  */
 
 // Need to include something before #if SK_SUPPORT_GPU so that the Android
 // framework build, which gets its defines from SkTypes rather than a makefile,
 // has the definition before checking it.
@@ skipping 68 matching lines @@
 
 class AutoMPDReset : SkNoncopyable {
     SkMultiPictureDraw* fMPD;
 public:
     AutoMPDReset(SkMultiPictureDraw* mpd) : fMPD(mpd) {}
     ~AutoMPDReset() { fMPD->reset(); }
 };
 
 //#define FORCE_SINGLE_THREAD_DRAWING_FOR_TESTING
 
-void SkMultiPictureDraw::draw() {
+void SkMultiPictureDraw::draw(bool flush) {
     AutoMPDReset mpdreset(this);
 
 #ifdef FORCE_SINGLE_THREAD_DRAWING_FOR_TESTING
     for (int i = 0; i < fThreadSafeDrawData.count(); ++i) {
         DrawData* dd = &fThreadSafeDrawData.begin()[i];
         dd->fCanvas->drawPicture(dd->fPicture, &dd->fMatrix, dd->fPaint);
     }
 #else
     // we place the taskgroup after the MPDReset, to ensure that we don't delete the DrawData
     // objects until after we're finished the tasks (which have pointers to the data).
@@ skipping 85 matching lines @@
             GrLayerHoister::UnlockLayers(context, needRendering);
             GrLayerHoister::UnlockLayers(context, recycled);
 
             needRendering.rewind();
             recycled.rewind();
         } else
 #endif
         {
             canvas->drawPicture(picture, &data.fMatrix, data.fPaint);
         }
+        if (flush) {
+            canvas->flush();
+        }
     }
 
 #if !defined(SK_IGNORE_GPU_LAYER_HOISTING) && SK_SUPPORT_GPU
     GrLayerHoister::UnlockLayers(context, atlasedNeedRendering);
     GrLayerHoister::UnlockLayers(context, atlasedRecycled);
 #if !GR_CACHE_HOISTED_LAYERS
     GrLayerHoister::PurgeCache(context);
 #endif
 #endif
 }