skia: Add support for CHROMIUM_image backed textures.

include/core/SkSurface.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkSurface_DEFINED
 #define SkSurface_DEFINED
 
@@ skipping 95 matching lines @@
      *  Used to wrap a pre-existing 3D API rendering target as a SkSurface. Skia will not assume
      *  ownership of the render target and the client must ensure the render target is valid for the
      *  lifetime of the SkSurface.
      */
     static SkSurface* NewFromBackendRenderTarget(GrContext*, const GrBackendRenderTargetDesc&,
                                                  const SkSurfaceProps*);
 
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface.
+     *
+     *  |customAllocator|, if present, must be an instance of TextureStorageAllocator.
      */
     static SkSurface* NewRenderTarget(GrContext*, Budgeted, const SkImageInfo&, int sampleCount,
-                                      const SkSurfaceProps* = NULL);
+                                      const SkSurfaceProps* = NULL, void* customAllocator = NULL);

[erikchen, 2016/01/26 18:36:16]

I wasn't sure what type of interface you wanted. I could add a member to
SkSurfaceProps, or I could create another Abstract base class in SkTypes, which
the GrType allocator inherits from. Or I could just pass around a void*. Your
call.

[bsalomon, 2016/01/26 22:20:54]

Why not just pass GrTextureStorageAllocator* here?

[erikchen, 2016/01/27 21:55:14]

Oops, fixed.

 
     static SkSurface* NewRenderTarget(GrContext* gr, Budgeted b, const SkImageInfo& info) {
-        return NewRenderTarget(gr, b, info, 0, NULL);
+        return NewRenderTarget(gr, b, info, 0, NULL, NULL);
     }
 
     int width() const { return fWidth; }
     int height() const { return fHeight; }
 
     /**
      *  Returns a unique non-zero, unique value identifying the content of this
      *  surface. Each time the content is changed changed, either by drawing
      *  into this surface, or explicitly calling notifyContentChanged()) this
      *  method will return a new value.
@@ skipping 149 matching lines @@
 private:
     const SkSurfaceProps fProps;
     const int            fWidth;
     const int            fHeight;
     uint32_t             fGenerationID;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif