Revise system for checking for uninstantiated proxies

The new pattern is:
  we will "instantiate" pipelines at flush time
  at flush time we will only access the backing GrSurface by peeking

  If instantiation fails we should never try to access the GrSurfaces


Change-Id: I87f7ff41bd0e84d9ca3dbdd61d3361d3d4ceefd6
Reviewed-on: https://skia-review.googlesource.com/17932
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/effects/GrTextureDomain.cpp b/src/gpu/effects/GrTextureDomain.cpp
index ee21841..1a6db7a 100644
--- a/src/gpu/effects/GrTextureDomain.cpp
+++ b/src/gpu/effects/GrTextureDomain.cpp
@@ -309,7 +309,9 @@
                        const GrFragmentProcessor& fp) override {
             const GrTextureDomainEffect& tde = fp.cast<GrTextureDomainEffect>();
             const GrTextureDomain& domain = tde.fTextureDomain;
-            fGLDomain.setData(pdman, domain, tde.textureSampler(0).texture());
+            GrTexture* texture =  tde.textureSampler(0).peekTexture();
+
+            fGLDomain.setData(pdman, domain, texture);
             if (SkToBool(tde.colorSpaceXform())) {
                 fColorSpaceHelper.setData(pdman, tde.colorSpaceXform());
             }
@@ -412,7 +414,8 @@
                        const GrFragmentProcessor& fp) override {
             const GrDeviceSpaceTextureDecalFragmentProcessor& dstdfp =
                     fp.cast<GrDeviceSpaceTextureDecalFragmentProcessor>();
-            GrTexture* texture = dstdfp.textureSampler(0).texture();
+            GrTexture* texture = dstdfp.textureSampler(0).peekTexture();
+
             fGLDomain.setData(pdman, dstdfp.fTextureDomain, texture);
             float iw = 1.f / texture->width();
             float ih = 1.f / texture->height();