Make RasterCache responsible for prerolling the image

sky/compositor/picture_layer.cc

@@ -8,8 +8,6 @@
 #include "sky/compositor/checkerboard.h"
 #include "sky/compositor/raster_cache.h"
 
-#define ENABLE_RASTER_CACHE 0
-
 namespace sky {
 namespace compositor {
 
@@ -24,13 +22,8 @@ PictureLayer::~PictureLayer() {
 
 void PictureLayer::Preroll(PaintContext::ScopedFrame& frame,
                            const SkMatrix& matrix) {
-#if ENABLE_RASTER_CACHE
-  image_ = frame.context().raster_cache().GetImage(picture_.get(), matrix);
-  if (image_) {
-    image_->preroll(frame.gr_context(), SkShader::kClamp_TileMode,
-                    SkShader::kClamp_TileMode, kMedium_SkFilterQuality);
-  }
-#endif
+  image_ = frame.context().raster_cache().GetPrerolledImage(
+      frame.gr_context(), picture_.get(), matrix);
 }
 
 void PictureLayer::Paint(PaintContext::ScopedFrame& frame) {

sky/compositor/raster_cache.cc

@@ -8,6 +8,8 @@
 #include "base/logging.h"
 #include "third_party/skia/include/core/SkImage.h"
 
+#define ENABLE_RASTER_CACHE 0
+
 namespace sky {
 namespace compositor {
 
@@ -32,7 +34,10 @@ RasterCache::Entry::Entry() {
 RasterCache::Entry::~Entry() {
 }
 
-RefPtr<SkImage> RasterCache::GetImage(SkPicture* picture, const SkMatrix& ctm) {
+RefPtr<SkImage> RasterCache::GetPrerolledImage(GrContext* context,
+                                               SkPicture* picture,
+                                               const SkMatrix& ctm) {
+#if ENABLE_RASTER_CACHE
   SkScalar scaleX = ctm.getScaleX();
   SkScalar scaleY = ctm.getScaleY();
 
@@ -67,10 +72,15 @@ RefPtr<SkImage> RasterCache::GetImage(SkPicture* picture, const SkMatrix& ctm) {
       SkMatrix matrix = SkMatrix::MakeScale(scaleX, scaleY);
       entry.image = adoptRef(SkImage::NewFromPicture(picture, physical_size,
                                                      &matrix, nullptr));
+      entry.image->preroll(context, SkShader::kClamp_TileMode,
+                           SkShader::kClamp_TileMode, kMedium_SkFilterQuality);
     }
   }
 
   return entry.image;
+#else
+  return nullptr;
+#endif
 }
 
 void RasterCache::SweepAfterFrame() {

sky/compositor/raster_cache.h

@@ -23,7 +23,8 @@ class RasterCache {
   RasterCache();
   ~RasterCache();
 
-  RefPtr<SkImage> GetImage(SkPicture* picture, const SkMatrix& ctm);
+  RefPtr<SkImage> GetPrerolledImage(GrContext* context, SkPicture* picture,
+                                    const SkMatrix& ctm);
   void SweepAfterFrame();
 
  private: