Guard runtime shader/colorfilter against SkSL that doesn't compile

Bug: oss-fuzz:20555
Bug: chromium:1051911
Change-Id: If40137e6cf3c0d398a86023c2399ddb7df10e209
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/270442
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>

Author: brianosman

src/core/SkColorFilter.cpp

@@ -491,6 +491,10 @@ sk_sp<SkFlattenable> SkRuntimeColorFilter::CreateProc(SkReadBuffer& buffer) {
     }
 
     auto effect = std::get<0>(SkRuntimeEffect::Make(std::move(sksl)));
+    if (!effect) {
+        return nullptr;
+    }
+
     return effect->makeColorFilter(std::move(inputs), children.data(), children.size());
 }
 

src/shaders/SkRTShader.cpp

@@ -117,6 +117,10 @@ sk_sp<SkFlattenable> SkRTShader::CreateProc(SkReadBuffer& buffer) {
     }
 
     auto effect = std::get<0>(SkRuntimeEffect::Make(std::move(sksl)));
+    if (!effect) {
+        return nullptr;
+    }
+
     return effect->makeShader(std::move(inputs), children.data(), children.size(), localMPtr,
                               isOpaque);
 }