Enable flattening/unflattening with custom unflatten procs

src/core/SkValidatingReadBuffer.cpp

Index: src/core/SkValidatingReadBuffer.cpp
diff --git a/src/core/SkValidatingReadBuffer.cpp b/src/core/SkValidatingReadBuffer.cpp
index ad4b6c409e6a0adca7c85b87c69a59089ac76779..95c4d196bea34234084b17d1d981ee6339d9d842 100644
--- a/src/core/SkValidatingReadBuffer.cpp
+++ b/src/core/SkValidatingReadBuffer.cpp
@@ -236,28 +236,26 @@ SkFlattenable* SkValidatingReadBuffer::readFlattenable(SkFlattenable::Type type)
         return nullptr;
     }
 
-    SkFlattenable::Factory factory = SkFlattenable::NameToFactory(cname);
-    if (nullptr == factory) {
-        return nullptr; // writer failed to give us the flattenable
+    // Get the factory for this flattenable.
+    SkFlattenable::Factory factory = getCustomFactory(cname);
+    if (!factory) {
+        factory = SkFlattenable::NameToFactory(cname);
+        if (!factory) {
+            return nullptr; // writer failed to give us the flattenable
+        }
     }
 
     // if we get here, factory may still be null, but if that is the case, the
     // failure was ours, not the writer.
     sk_sp<SkFlattenable> obj;
     uint32_t sizeRecorded = this->readUInt();
-    if (factory) {
-        size_t offset = fReader.offset();
-        obj = (*factory)(*this);
-        // check that we read the amount we expected
-        size_t sizeRead = fReader.offset() - offset;
-        this->validate(sizeRecorded == sizeRead);
-        if (fError) {
-            obj = nullptr;
-        }
-    } else {
-        // we must skip the remaining data
-        this->skip(sizeRecorded);
-        SkASSERT(false);
+    size_t offset = fReader.offset();
+    obj = (*factory)(*this);
+    // check that we read the amount we expected
+    size_t sizeRead = fReader.offset() - offset;
+    this->validate(sizeRecorded == sizeRead);
+    if (fError) {
+        obj = nullptr;
     }
     return obj.release();
 }