Add new Codec fuzzers to FuzzMain

Already in oss-fuzz:
https://github.com/google/oss-fuzz/pull/1882

This tweaks some names and return types to be more
consistent.

Bug: skia:
Change-Id: Id7e2e00bd4e7c7758d616d102195c0291bc37d9f
Reviewed-on: https://skia-review.googlesource.com/c/163124
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
diff --git a/fuzz/oss_fuzz/FuzzImage.cpp b/fuzz/oss_fuzz/FuzzImage.cpp
index 0a8c87a..735eb9c 100644
--- a/fuzz/oss_fuzz/FuzzImage.cpp
+++ b/fuzz/oss_fuzz/FuzzImage.cpp
@@ -11,27 +11,27 @@
 #include "SkData.h"
 #include "SkSurface.h"
 
-void FuzzImage(sk_sp<SkData> bytes) {
+bool FuzzImageDecode(sk_sp<SkData> bytes) {
     auto img = SkImage::MakeFromEncoded(bytes);
     if (nullptr == img.get()) {
-        return;
+        return false;
     }
 
     auto s = SkSurface::MakeRasterN32Premul(128, 128);
     if (!s) {
         // May return nullptr in memory-constrained fuzzing environments
-        return;
+        return false;
     }
 
     SkPaint p;
     s->getCanvas()->drawImage(img, 0, 0, &p);
-
+    return true;
 }
 
 #if defined(IS_FUZZING_WITH_LIBFUZZER)
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     auto bytes = SkData::MakeWithoutCopy(data, size);
-    FuzzImage(bytes);
+    FuzzImageDecode(bytes);
     return 0;
 }
 #endif