skia: Add support for CHROMIUM_image backed textures.

I created a new abstract base class TextureStorageAllocator that consumers of
Skia can subclass and pass back to Skia. When a surface is created with a
pointer to a TextureStorageAllocator, any textures it creates, or that are
derived from the original surface, will allocate and deallocate storage using
the methods on TextureStorageAllocator.

BUG=https://code.google.com/p/chromium/issues/detail?id=579664
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1623653002

Committed: https://skia.googlesource.com/skia/+/92098e691f10a010e7421125ba4d44c02506bb55

Review URL: https://codereview.chromium.org/1623653002

1 files changed, 7 insertions, 3 deletions

diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index 52097be66e..45262d78e6 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -120,12 +120,16 @@ public:
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface.
+     *
+     *  The GrTextureStorageAllocator will be reused if SkImage snapshots create
+     *  additional textures.
      */
-    static SkSurface* NewRenderTarget(GrContext*, Budgeted, const SkImageInfo&, int sampleCount,
-                                      const SkSurfaceProps* = NULL);
+    static SkSurface* NewRenderTarget(
+            GrContext*, Budgeted, const SkImageInfo&, int sampleCount, const SkSurfaceProps* = NULL,
+            GrTextureStorageAllocator = GrTextureStorageAllocator());
 
     static SkSurface* NewRenderTarget(GrContext* gr, Budgeted b, const SkImageInfo& info) {
-        return NewRenderTarget(gr, b, info, 0, NULL);
+        return NewRenderTarget(gr, b, info, 0);
     }
 
     int width() const { return fWidth; }