Fix LSAN leak warnings in feature_policy_fuzzer

This moves logic to handle LSAN leak warnings into ~BlinkFuzzerTestSupport.
Two related call sites are updated.

Bug: chromium:906425
Change-Id: I2b7c6d5145e67a3d9d919e5f17e51a28eacee7bc
Reviewed-on: https://chromium-review.googlesource.com/c/1341522Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Abhishek Arya <inferno@chromium.org>
Reviewed-by: Ian Clelland <iclelland@chromium.org>
Commit-Queue: Abhishek Arya <inferno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610280}

third_party/blink/renderer/core/css/parser/css_parser_fast_paths_fuzzer.cc

@@ -31,12 +31,5 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
         static_cast<blink::CSSParserMode>(parser_mode));
   }
 
-#if defined(ADDRESS_SANITIZER)
-  // LSAN needs unreachable objects to be released to avoid reporting them
-  // incorrectly as a memory leak.
-  blink::ThreadState* currentThreadState = blink::ThreadState::Current();
-  currentThreadState->CollectAllGarbage();
-#endif
-
   return 0;
 }

third_party/blink/renderer/core/css/style_sheet_contents_fuzzer.cc

@@ -27,13 +27,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   styleSheet->ParseString(String::FromUTF8WithLatin1Fallback(
       reinterpret_cast<const char*>(data), size));
 
-#if defined(ADDRESS_SANITIZER)
-  // LSAN needs unreachable objects to be released to avoid reporting them
-  // incorrectly as a memory leak.
-  blink::ThreadState* currentThreadState = blink::ThreadState::Current();
-  currentThreadState->CollectAllGarbage();
-#endif
-
   return 0;
 }
 

third_party/blink/renderer/platform/testing/blink_fuzzer_test_support.cc

@@ -8,6 +8,7 @@
 #include "base/command_line.h"
 #include "base/i18n/icu_util.h"
 #include "content/public/test/blink_test_environment.h"
+#include "third_party/blink/renderer/platform/heap/thread_state.h"
 #include "third_party/blink/renderer/platform/weborigin/scheme_registry.h"
 
 namespace blink {
@@ -30,6 +31,13 @@ BlinkFuzzerTestSupport::BlinkFuzzerTestSupport(int argc, char** argv) {
   blink::SchemeRegistry::Initialize();
 }
 
-BlinkFuzzerTestSupport::~BlinkFuzzerTestSupport() = default;
+BlinkFuzzerTestSupport::~BlinkFuzzerTestSupport() {
+#if defined(ADDRESS_SANITIZER)
+  // LSAN needs unreachable objects to be released to avoid reporting them
+  // incorrectly as a memory leak.
+  blink::ThreadState* currentThreadState = blink::ThreadState::Current();
+  currentThreadState->CollectAllGarbage();
+#endif
+}
 
 }  // namespace blink