Replace scoped_ptr With std::unique_ptr

(This is a merge of http://go/wvgerrit/65782)

We have had our own scoped_ptr implementation that is used throughout
the codebase. Now that we support C++11, we can replace these with
std::unique_ptr.

Doing this replacement exposed a few places where the two were not
interchangeable. OEMCrypto Ref was doing some unsafe things with passing
scoped_ptrs to functions and has been updated to use move semantics. And
a few constructors were explicitly constructing a scoped_ptr with NULL,
which is ambiguous with std::unique_ptr. These have been replaced with
default constructor calls.

Bug: 111851141
Test: CE CDM Unit Tests
Test: Android Unit Tests
Change-Id: I37d6d7aad4906709381c74f0c5439f826d2be768

libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_device_properties_prov30.cpp

@@ -12,6 +12,8 @@
 
 #include <string.h>
 
+#include <utility>
+
 #include "log.h"
 #include "oem_cert.h"
 
@@ -19,8 +21,8 @@ namespace wvoec_ref {
 
 class Prov30CryptoEngine : public CryptoEngine {
  public:
-  explicit Prov30CryptoEngine(scoped_ptr<wvcdm::FileSystem> file_system)
-      : CryptoEngine(file_system) {}
+  explicit Prov30CryptoEngine(std::unique_ptr<wvcdm::FileSystem>&& file_system)
+      : CryptoEngine(std::move(file_system)) {}
 
   bool config_local_display_only() { return true; }
 
@@ -77,8 +79,8 @@ class Prov30CryptoEngine : public CryptoEngine {
 };
 
 CryptoEngine* CryptoEngine::MakeCryptoEngine(
-    scoped_ptr<wvcdm::FileSystem> file_system) {
-  return new Prov30CryptoEngine(file_system);
+    std::unique_ptr<wvcdm::FileSystem>&& file_system) {
+  return new Prov30CryptoEngine(std::move(file_system));
 }
 
 }  // namespace wvoec_ref