Add operator int() to unique_fd.

Change-Id: I7512559be7befbb8772d5529e06550267a2f1543
diff --git a/libmemunreachable/ProcessMappings.cpp b/libmemunreachable/ProcessMappings.cpp
index 7cca7c1..57b2321 100644
--- a/libmemunreachable/ProcessMappings.cpp
+++ b/libmemunreachable/ProcessMappings.cpp
@@ -30,11 +30,10 @@
 bool ProcessMappings(pid_t pid, allocator::vector<Mapping>& mappings) {
   char map_buffer[1024];
   snprintf(map_buffer, sizeof(map_buffer), "/proc/%d/maps", pid);
-  int fd = open(map_buffer, O_RDONLY);
-  if (fd < 0) {
+  android::base::unique_fd fd(open(map_buffer, O_RDONLY));
+  if (fd == -1) {
     return false;
   }
-  android::base::unique_fd fd_guard{fd};
 
   LineBuffer line_buf(fd, map_buffer, sizeof(map_buffer));
   char* line;
diff --git a/libmemunreachable/ThreadCapture.cpp b/libmemunreachable/ThreadCapture.cpp
index e8a8392..9155c29 100644
--- a/libmemunreachable/ThreadCapture.cpp
+++ b/libmemunreachable/ThreadCapture.cpp
@@ -108,12 +108,11 @@
   strlcat(path, pid_str, sizeof(path));
   strlcat(path, "/task", sizeof(path));
 
-  int fd = open(path, O_CLOEXEC | O_DIRECTORY | O_RDONLY);
-  if (fd < 0) {
+  android::base::unique_fd fd(open(path, O_CLOEXEC | O_DIRECTORY | O_RDONLY));
+  if (fd == -1) {
     ALOGE("failed to open %s: %s", path, strerror(errno));
     return false;
   }
-  android::base::unique_fd fd_guard{fd};
 
   struct linux_dirent64 {
     uint64_t  d_ino;
@@ -125,7 +124,7 @@
   char dirent_buf[4096];
   ssize_t nread;
   do {
-    nread = syscall(SYS_getdents64, fd, dirent_buf, sizeof(dirent_buf));
+    nread = syscall(SYS_getdents64, fd.get(), dirent_buf, sizeof(dirent_buf));
     if (nread < 0) {
       ALOGE("failed to get directory entries from %s: %s", path, strerror(errno));
       return false;
diff --git a/libmemunreachable/tests/ThreadCapture_test.cpp b/libmemunreachable/tests/ThreadCapture_test.cpp
index cefe94e..41ed84e 100644
--- a/libmemunreachable/tests/ThreadCapture_test.cpp
+++ b/libmemunreachable/tests/ThreadCapture_test.cpp
@@ -28,8 +28,6 @@
 
 #include <gtest/gtest.h>
 
-#include <android-base/unique_fd.h>
-
 #include "Allocator.h"
 #include "ScopedDisableMalloc.h"
 #include "ScopedPipe.h"