Replace scoped_ptr with unique_ptr in webrtc/base/

This propagated into various other places. Also had to #include headers that
were implicitly pulled by "scoped_ptr.h".

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1920043002

Cr-Commit-Position: refs/heads/master@{#12501}
diff --git a/webrtc/base/sslidentity_unittest.cc b/webrtc/base/sslidentity_unittest.cc
index f110f76..e108b7d 100644
--- a/webrtc/base/sslidentity_unittest.cc
+++ b/webrtc/base/sslidentity_unittest.cc
@@ -8,6 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include <memory>
 #include <string>
 
 #include "webrtc/base/gunit.h"
@@ -174,11 +175,11 @@
   }
 
  private:
-  rtc::scoped_ptr<SSLIdentity> identity_rsa1_;
-  rtc::scoped_ptr<SSLIdentity> identity_rsa2_;
-  rtc::scoped_ptr<SSLIdentity> identity_ecdsa1_;
-  rtc::scoped_ptr<SSLIdentity> identity_ecdsa2_;
-  rtc::scoped_ptr<rtc::SSLCertificate> test_cert_;
+  std::unique_ptr<SSLIdentity> identity_rsa1_;
+  std::unique_ptr<SSLIdentity> identity_rsa2_;
+  std::unique_ptr<SSLIdentity> identity_ecdsa1_;
+  std::unique_ptr<SSLIdentity> identity_ecdsa2_;
+  std::unique_ptr<rtc::SSLCertificate> test_cert_;
 };
 
 TEST_F(SSLIdentityTest, FixedDigestSHA1) {
@@ -251,7 +252,7 @@
       "UD0A8qfhfDM+LK6rPAnCsVN0NRDY3jvd6rzix9M=\n"
       "-----END CERTIFICATE-----\n";
 
-  rtc::scoped_ptr<SSLIdentity> identity(
+  std::unique_ptr<SSLIdentity> identity(
       SSLIdentity::FromPEMStrings(kRSA_PRIVATE_KEY_PEM, kCERT_PEM));
   EXPECT_TRUE(identity);
   EXPECT_EQ(kCERT_PEM, identity->certificate().ToPEMString());
@@ -278,7 +279,7 @@
       "GWP/PwIgJynB4AUDsPT0DWmethOXYijB5sY5UPd9DvgmiS/Mr6s=\n"
       "-----END CERTIFICATE-----\n";
 
-  rtc::scoped_ptr<SSLIdentity> identity(
+  std::unique_ptr<SSLIdentity> identity(
       SSLIdentity::FromPEMStrings(kRSA_PRIVATE_KEY_PEM, kCERT_PEM));
   EXPECT_TRUE(identity);
   EXPECT_EQ(kCERT_PEM, identity->certificate().ToPEMString());