impl preroll for all image backends

BUG=skia:

Review URL: https://codereview.chromium.org/1341043002

3 files changed, 8 insertions, 12 deletions

diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 4315ad7e87..654b848fce 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -55,7 +55,14 @@ bool SkImage::readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dst
 }
 
 void SkImage::preroll(GrContext* ctx) const {
-    as_IB(this)->onPreroll(ctx);
+    // For now, and to maintain parity w/ previous pixelref behavior, we just force the image
+    // to produce a cached raster-bitmap form, so that drawing to a raster canvas should be fast.
+    //
+    SkBitmap bm;
+    if (as_IB(this)->getROPixels(&bm)) {
+        bm.lockPixels();
+        bm.unlockPixels();
+    }
 }
 
 SkShader* SkImage::newShader(SkShader::TileMode tileX,
diff --git a/src/image/SkImage_Base.h b/src/image/SkImage_Base.h
index 8c9a73ba36..d316267647 100644
--- a/src/image/SkImage_Base.h
+++ b/src/image/SkImage_Base.h
@@ -52,8 +52,6 @@ public:
     virtual bool onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                               int srcX, int srcY) const;
 
-    virtual void onPreroll(GrContext*) const {}
-
     virtual GrTexture* peekTexture() const { return nullptr; }
 
     // return a read-only copy of the pixels. We promise to not modify them,
diff --git a/src/image/SkImage_Raster.cpp b/src/image/SkImage_Raster.cpp
index 5025dfa8c4..7eff9ef0f6 100644
--- a/src/image/SkImage_Raster.cpp
+++ b/src/image/SkImage_Raster.cpp
@@ -64,7 +64,6 @@ public:
 
     SkSurface* onNewSurface(const SkImageInfo&, const SkSurfaceProps&) const override;
     bool onReadPixels(const SkImageInfo&, void*, size_t, int srcX, int srcY) const override;
-    void onPreroll(GrContext*) const override;
     const void* onPeekPixels(SkImageInfo*, size_t* /*rowBytes*/) const override;
     SkData* onRefEncoded() const override;
     bool getROPixels(SkBitmap*) const override;
@@ -164,14 +163,6 @@ const void* SkImage_Raster::onPeekPixels(SkImageInfo* infoPtr, size_t* rowBytesP
     return fBitmap.getPixels();
 }
 
-void SkImage_Raster::onPreroll(GrContext* ctx) const {
-    // SkImage can be called from lots of threads, but our fBitmap is *not* thread-safe,
-    // so we have to perform this lock/unlock in a non-racy way... we make a copy!
-    SkBitmap localShallowCopy(fBitmap);
-    localShallowCopy.lockPixels();
-    localShallowCopy.unlockPixels();
-}
-
 SkData* SkImage_Raster::onRefEncoded() const {
     SkPixelRef* pr = fBitmap.pixelRef();
     const SkImageInfo prInfo = pr->info();