Revert "Revert "Add GrRenderTargetContext instantiate & asTextureProxy""

This reverts commit 7d7d7d19462b75f5470492dc4820a02c1eba4af2.

Reason for revert: Reverting this to see if it really was crashing on SVGs or if that was cross talk.

Original change's description:
> Revert "Add GrRenderTargetContext instantiate & asTextureProxy"
> 
> This reverts commit 9113edfff89e657dabc0ba095c54f7720550196c.
> 
> Reason for revert: Looks to be causing EXCEPTION_ACCESS_VIOLATION:
> 
> https://uberchromegw.corp.google.com/i/client.skia/builders/Test-Win-MSVC-NUC-GPU-IntelIris6100-x86_64-Debug/builds/121/steps/test_skia%20on%20Windows/logs/stdio
> https://uberchromegw.corp.google.com/i/client.skia/builders/Test-Win-MSVC-GCE-CPU-AVX2-x86-Debug/builds/2384/steps/test_skia%20on%20Windows-2008ServerR2-SP1/logs/stdio
> https://uberchromegw.corp.google.com/i/client.skia/builders/Test-Win-MSVC-ShuttleC-GPU-iHD530-x86_64-Debug/builds/785/steps/test_skia%20on%20Windows/logs/stdio
> 
> Original change's description:
> > Add GrRenderTargetContext instantiate & asTextureProxy
> > 
> > This CL also centralizes the instantiation code in GrSurfaceProxy and adds a test.
> > 
> > GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4494
> > 
> > Change-Id: I0081d9a216dc0af293179f23bcb88acf6a822324
> > Reviewed-on: https://skia-review.googlesource.com/4494
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Commit-Queue: Robert Phillips <robertphillips@google.com>
> > 
> 
> TBR=bsalomon@google.com,robertphillips@google.com,reviews@skia.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> 
> Change-Id: I225ce7867ebd445067e5ea55ebbfd587f7fe782a
> Reviewed-on: https://skia-review.googlesource.com/4528
> Commit-Queue: Leon Scroggins <scroggo@google.com>
> Reviewed-by: Leon Scroggins <scroggo@google.com>
> 

TBR=bsalomon@google.com,robertphillips@google.com,scroggo@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: Ifc3b9ac343009a3808f5f47500eef50df438e3d9
Reviewed-on: https://skia-review.googlesource.com/4537
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/include/private/GrSurfaceProxy.h b/include/private/GrSurfaceProxy.h
index e748853..539aaf6 100644
--- a/include/private/GrSurfaceProxy.h
+++ b/include/private/GrSurfaceProxy.h
@@ -13,6 +13,7 @@
 #include "SkRect.h"
 
 class GrOpList;
+class GrTextureProvider;
 class GrTextureProxy;
 class GrRenderTargetProxy;
 
@@ -127,6 +128,8 @@
         return fGpuMemorySize;
     }
 
+    bool isWrapped_ForTesting() const;
+
 protected:
     // Deferred version
     GrSurfaceProxy(const GrSurfaceDesc& desc, SkBackingFit fit, SkBudgeted budgeted)
@@ -143,6 +146,8 @@
 
     virtual ~GrSurfaceProxy();
 
+    GrSurface* instantiate(GrTextureProvider* texProvider);
+
     // For wrapped resources, 'fDesc' will always be filled in from the wrapped resource.
     const GrSurfaceDesc fDesc;
     const SkBackingFit  fFit;      // always exact for wrapped resources