Add SkSurface factory for wrapping an FBO in SkSurface

src/image/SkSurface_Gpu.cpp

Index: src/image/SkSurface_Gpu.cpp
diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index 71bed3a9b9083a70bbc1afc9603f61df66ee0ea5..ef64db576de57c09a063c1d0c0f784a150d9837c 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -117,8 +117,8 @@ SkSurface* SkSurface::NewRenderTarget(GrContext* ctx, Budgeted budgeted, const S
     return SkNEW_ARGS(SkSurface_Gpu, (device));
 }
 
-SkSurface* SkSurface::NewWrappedRenderTarget(GrContext* context, GrBackendTextureDesc desc,
-                                             const SkSurfaceProps* props) {
+SkSurface* SkSurface::NewFromBackendTexture(GrContext* context, const GrBackendTextureDesc& desc,
+                                            const SkSurfaceProps* props) {
     if (NULL == context) {
         return NULL;
     }
@@ -138,4 +138,22 @@ SkSurface* SkSurface::NewWrappedRenderTarget(GrContext* context, GrBackendTextur
     return SkNEW_ARGS(SkSurface_Gpu, (device));
 }
 
+SkSurface* SkSurface::NewFromBackendRenderTarget(GrContext* context,
+                                                 const GrBackendRenderTargetDesc& desc,
+                                                 const SkSurfaceProps* props) {
+    if (NULL == context) {
+        return NULL;
+    }
+    SkAutoTUnref<GrRenderTarget> rt(context->textureProvider()->wrapBackendRenderTarget(desc));
+    if (!rt) {
+        return NULL;
+    }
+    SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(rt, props,
+                                                         SkGpuDevice::kUninit_InitContents));
+    if (!device) {
+        return NULL;
+    }
+    return SkNEW_ARGS(SkSurface_Gpu, (device));
+}
+
 #endif