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/messagequeue.h b/webrtc/base/messagequeue.h
index efc479c..d323283 100644
--- a/webrtc/base/messagequeue.h
+++ b/webrtc/base/messagequeue.h
@@ -15,6 +15,7 @@
 
 #include <algorithm>
 #include <list>
+#include <memory>
 #include <queue>
 #include <vector>
 
@@ -22,7 +23,6 @@
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/messagehandler.h"
-#include "webrtc/base/scoped_ptr.h"
 #include "webrtc/base/scoped_ref_ptr.h"
 #include "webrtc/base/sharedexclusivelock.h"
 #include "webrtc/base/sigslot.h"
@@ -89,10 +89,11 @@
 class ScopedMessageData : public MessageData {
  public:
   explicit ScopedMessageData(T* data) : data_(data) { }
-  const scoped_ptr<T>& data() const { return data_; }
-  scoped_ptr<T>& data() { return data_; }
+  const std::unique_ptr<T>& data() const { return data_; }
+  std::unique_ptr<T>& data() { return data_; }
+
  private:
-  scoped_ptr<T> data_;
+  std::unique_ptr<T> data_;
 };
 
 // Like ScopedMessageData, but for reference counted pointers.
@@ -278,7 +279,7 @@
   // The SocketServer is not owned by MessageQueue.
   SocketServer* ss_ GUARDED_BY(ss_lock_);
   // If a server isn't supplied in the constructor, use this one.
-  scoped_ptr<SocketServer> default_ss_;
+  std::unique_ptr<SocketServer> default_ss_;
   SharedExclusiveLock ss_lock_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(MessageQueue);