SSLCertificate::GetChain: Return scoped_ptr

Instead of using a raw pointer output parameter. This is a good idea
in general, but will also be very convenient when scoped_ptr is gone,
since unique_ptr doesn't have an .accept() method.

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1799233002

Cr-Commit-Position: refs/heads/master@{#12004}

webrtc/api/statscollector.cc

@@ -575,8 +575,8 @@ StatsReport* StatsCollector::AddCertificateReports(
   RTC_DCHECK(cert != NULL);
 
   StatsReport* issuer = nullptr;
-  rtc::scoped_ptr<rtc::SSLCertChain> chain;
-  if (cert->GetChain(chain.accept())) {
+  rtc::scoped_ptr<rtc::SSLCertChain> chain = cert->GetChain();
+  if (chain) {
     // This loop runs in reverse, i.e. from root to leaf, so that each
     // certificate's issuer's report ID is known before the child certificate's
     // report is generated.  The root certificate does not have an issuer ID

webrtc/base/fakesslidentity.h

@@ -68,14 +68,14 @@ class FakeSSLCertificate : public rtc::SSLCertificate {
                                        digest, size);
     return (*length != 0);
   }
-  virtual bool GetChain(SSLCertChain** chain) const {
+  virtual rtc::scoped_ptr<SSLCertChain> GetChain() const {
     if (certs_.empty())
-      return false;
+      return nullptr;
     std::vector<SSLCertificate*> new_certs(certs_.size());
     std::transform(certs_.begin(), certs_.end(), new_certs.begin(), DupCert);
-    *chain = new SSLCertChain(new_certs);
+    rtc::scoped_ptr<SSLCertChain> chain(new SSLCertChain(new_certs));
     std::for_each(new_certs.begin(), new_certs.end(), DeleteCert);
-    return true;
+    return chain;
   }
 
  private:

webrtc/base/opensslidentity.cc

@@ -280,11 +280,11 @@ bool OpenSSLCertificate::GetSignatureDigestAlgorithm(
   return true;
 }
 
-bool OpenSSLCertificate::GetChain(SSLCertChain** chain) const {
+rtc::scoped_ptr<SSLCertChain> OpenSSLCertificate::GetChain() const {
   // Chains are not yet supported when using OpenSSL.
   // OpenSSLStreamAdapter::SSLVerifyCallback currently requires the remote
   // certificate to be self-signed.
-  return false;
+  return nullptr;
 }
 
 bool OpenSSLCertificate::ComputeDigest(const std::string& algorithm,

webrtc/base/opensslidentity.h

@@ -85,7 +85,7 @@ class OpenSSLCertificate : public SSLCertificate {
                             size_t* length);
 
   bool GetSignatureDigestAlgorithm(std::string* algorithm) const override;
-  bool GetChain(SSLCertChain** chain) const override;
+  rtc::scoped_ptr<SSLCertChain> GetChain() const override;
 
   int64_t CertificateExpirationTime() const override;
 

webrtc/base/sslidentity.h

@@ -19,6 +19,7 @@
 
 #include "webrtc/base/buffer.h"
 #include "webrtc/base/messagedigest.h"
+#include "webrtc/base/scoped_ptr.h"
 #include "webrtc/base/timeutils.h"
 
 namespace rtc {
@@ -50,9 +51,9 @@ class SSLCertificate {
   // Caller is responsible for freeing the returned object.
   virtual SSLCertificate* GetReference() const = 0;
 
-  // Provides the cert chain, or returns false.  The caller owns the chain.
-  // The chain includes a copy of each certificate, excluding the leaf.
-  virtual bool GetChain(SSLCertChain** chain) const = 0;
+  // Provides the cert chain, or null. The chain includes a copy of each
+  // certificate, excluding the leaf.
+  virtual rtc::scoped_ptr<SSLCertChain> GetChain() const = 0;
 
   // Returns a PEM encoded string representation of the certificate.
   virtual std::string ToPEMString() const = 0;

webrtc/base/sslstreamadapter_unittest.cc

@@ -1056,8 +1056,7 @@ TEST_F(SSLStreamAdapterTestDTLSFromPEMStrings, TestDTLSGetPeerCertificate) {
   ASSERT_NE(kCERT_PEM, client_peer_string);
 
   // It must not have a chain, because the test certs are self-signed.
-  rtc::SSLCertChain* client_peer_chain;
-  ASSERT_FALSE(client_peer_cert->GetChain(&client_peer_chain));
+  ASSERT_FALSE(client_peer_cert->GetChain());
 
   // The server should have a peer certificate after the handshake.
   ASSERT_TRUE(GetPeerCertificate(false, server_peer_cert.accept()));
@@ -1067,8 +1066,7 @@ TEST_F(SSLStreamAdapterTestDTLSFromPEMStrings, TestDTLSGetPeerCertificate) {
   ASSERT_EQ(kCERT_PEM, server_peer_cert->ToPEMString());
 
   // It must not have a chain, because the test certs are self-signed.
-  rtc::SSLCertChain* server_peer_chain;
-  ASSERT_FALSE(server_peer_cert->GetChain(&server_peer_chain));
+  ASSERT_FALSE(server_peer_cert->GetChain());
 }
 
 // Test getting the used DTLS ciphers.