Move out_result_ to first member in net::CertPathBuilder.

CertPathBuilder::cert_path_iter_ is constructed with a pointer to
out_result_, so out_result_ must be earlier in the member list to ensure
it is constructed before cert_path_iter_ tries to access it.

Bug: 997340,991247
Change-Id: I93137a16e0022db00d71b91b6636e42d6f39f2ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1769701Reviewed-by: Eric Roman <eroman@chromium.org>
Commit-Queue: Matt Mueller <mattm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690154}

net/cert/internal/path_builder.h

@@ -192,6 +192,10 @@ class NET_EXPORT CertPathBuilder {
  private:
   void AddResultPath(std::unique_ptr<CertPathBuilderResultPath> result_path);
 
+  // |out_result_| may be referenced by other members, so should be initialized
+  // first.
+  Result out_result_;
+
   std::unique_ptr<CertPathIter> cert_path_iter_;
   CertPathBuilderDelegate* delegate_;
   const der::GeneralizedTime time_;
@@ -203,8 +207,6 @@ class NET_EXPORT CertPathBuilder {
   uint32_t max_iteration_count_ = 0;
   base::TimeTicks deadline_;
 
-  Result out_result_;
-
   DISALLOW_COPY_AND_ASSIGN(CertPathBuilder);
 };
 

net/cert/internal/path_builder_unittest.cc

@@ -117,6 +117,49 @@ class AsyncCertIssuerSourceStatic : public CertIssuerSource {
   return ::testing::AssertionSuccess();
 }
 
+const void* kKey = &kKey;
+class TrustStoreThatStoresUserData : public TrustStore {
+ public:
+  class Data : public base::SupportsUserData::Data {
+   public:
+    explicit Data(int value) : value(value) {}
+
+    int value = 0;
+  };
+
+  // TrustStore implementation:
+  void SyncGetIssuersOf(const ParsedCertificate* cert,
+                        ParsedCertificateList* issuers) override {}
+  void GetTrust(const scoped_refptr<ParsedCertificate>& cert,
+                CertificateTrust* trust,
+                base::SupportsUserData* debug_data) const override {
+    debug_data->SetUserData(kKey, std::make_unique<Data>(1234));
+  }
+};
+
+TEST(PathBuilderResultUserDataTest, ModifyUserDataInConstructor) {
+  scoped_refptr<ParsedCertificate> a_by_b;
+  ASSERT_TRUE(ReadTestCert("multi-root-A-by-B.pem", &a_by_b));
+  SimplePathBuilderDelegate delegate(
+      1024, SimplePathBuilderDelegate::DigestPolicy::kWeakAllowSha1);
+  der::GeneralizedTime verify_time = {2017, 3, 1, 0, 0, 0};
+  TrustStoreThatStoresUserData trust_store;
+
+  // |trust_store| will unconditionally store user data in the
+  // CertPathBuilder::Result. This ensures that the Result object has been
+  // initialized before the first GetTrust call occurs (otherwise the test will
+  // crash or fail on ASAN bots).
+  CertPathBuilder path_builder(
+      a_by_b, &trust_store, &delegate, verify_time, KeyPurpose::ANY_EKU,
+      InitialExplicitPolicy::kFalse, {AnyPolicy()},
+      InitialPolicyMappingInhibit::kFalse, InitialAnyPolicyInhibit::kFalse);
+  CertPathBuilder::Result result = path_builder.Run();
+  auto* data = static_cast<TrustStoreThatStoresUserData::Data*>(
+      result.GetUserData(kKey));
+  ASSERT_TRUE(data);
+  EXPECT_EQ(1234, data->value);
+}
+
 class PathBuilderMultiRootTest : public ::testing::Test {
  public:
   PathBuilderMultiRootTest()