libchrome: Several upstreamable fixes from libchrome

base/files/file_util_posix.cc

Index: base/files/file_util_posix.cc
diff --git a/base/files/file_util_posix.cc b/base/files/file_util_posix.cc
index ca1c5250b920d310e0be12acb2a73a5cede3bddc..c5bbe0df904a0b0515f294dce4e4abe73c8c8aed 100644
--- a/base/files/file_util_posix.cc
+++ b/base/files/file_util_posix.cc
@@ -557,7 +557,7 @@ bool CreateTemporaryDirInDir(const FilePath& base_dir,
   return CreateTemporaryDirInDirImpl(base_dir, mkdtemp_template, new_dir);
 }
 
-bool CreateNewTempDirectory(const FilePath::StringType& prefix,
+bool CreateNewTempDirectory(const FilePath::StringType& /*prefix*/,
                             FilePath* new_temp_path) {
   FilePath tmpdir;
   if (!GetTempDir(&tmpdir))
@@ -845,6 +845,8 @@ bool GetShmemTempDir(bool executable, FilePath* path) {
     *path = FilePath("/dev/shm");
     return true;
   }
+#else
+  (void)executable;  // Avoid unused warning when !defined(OS_LINUX).
 #endif
   return GetTempDir(path);
 }