Create special surfaces according to original device (not always in N32)

src/effects/SkDisplacementMapEffect.cpp

Index: src/effects/SkDisplacementMapEffect.cpp
diff --git a/src/effects/SkDisplacementMapEffect.cpp b/src/effects/SkDisplacementMapEffect.cpp
index 8d068072a7454dd0f1f914ecdcae587d86b815f7..eeb0eff382d841567f43145a7da41179ed55afdc 100644
--- a/src/effects/SkDisplacementMapEffect.cpp
+++ b/src/effects/SkDisplacementMapEffect.cpp
@@ -279,7 +279,9 @@ sk_sp<SkSpecialImage> SkDisplacementMapEffect::onFilterImage(SkSpecialImage* sou
     }
 
     SkIPoint displOffset = SkIPoint::Make(0, 0);
-    sk_sp<SkSpecialImage> displ(this->filterInput(0, source, ctx, &displOffset));
+    // Creation of the displacement map should happen in a non-colorspace aware context:

[Brian Osman, 2016/09/23 13:44:08]

This is an arbitrary decision after a long discussion between Rob & I. The
correct answer here is ... not obvious.

[robertphillips, 2016/09/23 14:11:28]

Maybe expand on this to mention some of the consequences, when it matters ?

+    Context displContext(ctx.ctm(), ctx.clipBounds(), ctx.cache(), OutputProperties(nullptr));
+    sk_sp<SkSpecialImage> displ(this->filterInput(0, source, displContext, &displOffset));
     if (!displ) {
         return nullptr;
     }