remove RenderTargetFlags -- NewRenderTargetDirect will never clear

src/gpu/GrLayerHoister.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.
  */
 
 #include "GrLayerCache.h"
 #include "GrLayerHoister.h"
 #include "SkCanvas.h"
@@ skipping 125 matching lines @@
 
 void GrLayerHoister::DrawLayers(const SkPicture* picture,
                                 const SkTDArray<GrCachedLayer*>& atlased,
                                 const SkTDArray<GrCachedLayer*>& nonAtlased,
                                 GrReplacements* replacements) {
     // Render the atlased layers that require it
     if (atlased.count() > 0) {
         // All the atlased layers are rendered into the same GrTexture
         SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTargetDirect(
                                                 atlased[0]->texture()->asRenderTarget(),
-                                                SkSurface::kStandard_TextRenderMode,
-                                                SkSurface::kDontClear_RenderTargetFlag));
+                                                SkSurface::kStandard_TextRenderMode));
 
         SkCanvas* atlasCanvas = surface->getCanvas();
 
         SkPaint paint;
         paint.setColor(SK_ColorTRANSPARENT);
         paint.setXfermode(SkXfermode::Create(SkXfermode::kSrc_Mode))->unref();
 
         for (int i = 0; i < atlased.count(); ++i) {
             GrCachedLayer* layer = atlased[i];
 
@@ skipping 33 matching lines @@
         atlasCanvas->flush();
     }
 
     // Render the non-atlased layers that require it
     for (int i = 0; i < nonAtlased.count(); ++i) {
         GrCachedLayer* layer = nonAtlased[i];
 
         // Each non-atlased layer has its own GrTexture
         SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTargetDirect(
                                                 layer->texture()->asRenderTarget(),
-                                                SkSurface::kStandard_TextRenderMode,
-                                                SkSurface::kDontClear_RenderTargetFlag));
+                                                SkSurface::kStandard_TextRenderMode));
 
         SkCanvas* layerCanvas = surface->getCanvas();
 
         // Add a rect clip to make sure the rendering doesn't
         // extend beyond the boundaries of the atlased sub-rect
         SkRect bound = SkRect::MakeXYWH(SkIntToScalar(layer->rect().fLeft),
                                         SkIntToScalar(layer->rect().fTop),
                                         SkIntToScalar(layer->rect().width()),
                                         SkIntToScalar(layer->rect().height()));
 
@@ skipping 43 matching lines @@
 #if DISABLE_CACHING
     // This code completely clears out the atlas. It is required when
     // caching is disabled so the atlas doesn't fill up and force more
     // free floating layers
     layerCache->purge(picture->uniqueID());
 
     layerCache->purgeAll();
 #endif
 }