6 files changed, 21 insertions, 10 deletions
diff --git a/base/files/dir_reader_fallback.h b/base/files/dir_reader_fallback.h
index 4bc199a922..d44c2279e4 100644
--- a/base/files/dir_reader_fallback.h
+++ b/base/files/dir_reader_fallback.h
@@ -11,7 +11,7 @@ class DirReaderFallback {
  public:
   // Open a directory. If |IsValid| is true, then |Next| can be called to start
   // the iteration at the beginning of the directory.
-  explicit DirReaderFallback(const char* /* directory_path */) {}
+  explicit DirReaderFallback(const char* directory_path) {}
 
   // After construction, IsValid returns true iff the directory was
   // successfully opened.
diff --git a/base/files/file.h b/base/files/file.h
index 94a9d5cf49..0155c7c259 100644
--- a/base/files/file.h
+++ b/base/files/file.h
@@ -255,6 +255,16 @@ class BASE_EXPORT File {
 
   // Instructs the filesystem to flush the file to disk. (POSIX: fsync, Windows:
   // FlushFileBuffers).
+  // Calling Flush() does not guarantee file integrity and thus is not a valid
+  // substitute for file integrity checks and recovery codepaths for malformed
+  // files. It can also be *really* slow, so avoid blocking on Flush(),
+  // especially please don't block shutdown on Flush().
+  // Latency percentiles of Flush() across all platforms as of July 2016:
+  // 50 %     > 5 ms
+  // 10 %     > 58 ms
+  //  1 %     > 357 ms
+  //  0.1 %   > 1.8 seconds
+  //  0.01 %  > 7.6 seconds
   bool Flush();
 
   // Updates the file times.
diff --git a/base/files/file_path.cc b/base/files/file_path.cc
index 9f67f9bc49..5b1eb29dd6 100644
--- a/base/files/file_path.cc
+++ b/base/files/file_path.cc
@@ -53,8 +53,6 @@ StringPieceType::size_type FindDriveLetter(StringPieceType path) {
        (path[0] >= L'a' && path[0] <= L'z'))) {
     return 1;
   }
-#else
-  (void)path;  // Avoid an unused warning.
 #endif  // FILE_PATH_USES_DRIVE_LETTERS
   return StringType::npos;
 }
@@ -176,7 +174,7 @@ FilePath::FilePath() {
 
 FilePath::FilePath(const FilePath& that) : path_(that.path_) {
 }
-FilePath::FilePath(FilePath&& that) = default;
+FilePath::FilePath(FilePath&& that) noexcept = default;
 
 FilePath::FilePath(StringPieceType path) {
   path.CopyToString(&path_);
@@ -565,6 +563,12 @@ FilePath FilePath::StripTrailingSeparators() const {
 }
 
 bool FilePath::ReferencesParent() const {
+  if (path_.find(kParentDirectory) == StringType::npos) {
+    // GetComponents is quite expensive, so avoid calling it in the majority
+    // of cases where there isn't a kParentDirectory anywhere in the path.
+    return false;
+  }
+
   std::vector<StringType> components;
   GetComponents(&components);
 
@@ -1328,7 +1332,6 @@ FilePath FilePath::NormalizePathSeparatorsTo(CharType separator) const {
   }
   return FilePath(copy);
 #else
-  (void)separator;  // Avoid an unused warning.
   return *this;
 #endif
 }
diff --git a/base/files/file_path.h b/base/files/file_path.h
index 02846f6892..0be0ad0b10 100644
--- a/base/files/file_path.h
+++ b/base/files/file_path.h
@@ -184,7 +184,7 @@ class BASE_EXPORT FilePath {
 
   // Constructs FilePath with the contents of |that|, which is left in valid but
   // unspecified state.
-  FilePath(FilePath&& that);
+  FilePath(FilePath&& that) noexcept;
   // Replaces the contents with those of |that|, which is left in valid but
   // unspecified state.
   FilePath& operator=(FilePath&& that);
diff --git a/base/files/file_path_unittest.cc b/base/files/file_path_unittest.cc
index a091e62dd1..9f339527f5 100644
--- a/base/files/file_path_unittest.cc
+++ b/base/files/file_path_unittest.cc
@@ -1306,7 +1306,7 @@ TEST_F(FilePathTest, GetHFSDecomposedFormWithInvalidInput) {
     FPL("\xf0\x28\x8c\xbc"),
     FPL("\xf0\x28\x8c\x28"),
   };
-  for (const auto& invalid_input : cases) {
+  for (auto* invalid_input : cases) {
     FilePath::StringType observed = FilePath::GetHFSDecomposedForm(
         invalid_input);
     EXPECT_TRUE(observed.empty());
diff --git a/base/files/file_util_posix.cc b/base/files/file_util_posix.cc
index a03ca8d8d8..3501e241e9 100644
--- a/base/files/file_util_posix.cc
+++ b/base/files/file_util_posix.cc
@@ -628,7 +628,7 @@ 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))
@@ -934,8 +934,6 @@ 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);
 }