Add fuzzer for HTMLPreloadScanner

third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.h

Index: third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.h
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.h b/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.h
index 329795c691bc849b82ddb93bd3a6d6c097ca809a..471b1b95d6f851da42d5487da8ad88d0125b7134 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.h
+++ b/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.h
@@ -70,6 +70,10 @@ public:
     bool viewportMetaEnabled;
     ReferrerPolicy referrerPolicy;
 
+protected:
+    // For testing.
+    CachedDocumentParameters() {}

[kouhei (in TOK), 2016/08/22 05:48:28]

public:
static std::unique_ptr<CachedDocumentParameters> create() { return
wrapUnique(new CachedDocumentParameters); }

private:
CachedDocumentParameters() = default;
?

[Charlie Harrison, 2016/08/23 01:32:28]

I'm inclined to keep a protected constructor here because fuzzers are optimized
for stack allocations over heap allocations.

Given your other comment, though, it may be better for style to just do this.

[kouhei (in TOK), 2016/08/23 02:29:41]

I'm fine either way. Not a blocker.
However we seem to be heap alloc-ing this anyway in Fuzzer.cpp:
"CachedDocumentParametersForFuzzing* documentParameters = new
CachedDocumentParametersForFuzzing(fuzzedData);"

+
 private:
     explicit CachedDocumentParameters(Document*);
 };