[cleanup] Remove various unused IO functions from utils.h

Removes the following functions:
Flush
AppendChars
WriteAsCFile (only from header since impl was already removed)

and moves local function AppendChars into anonymous namespace block.

Bug: v8:9810
Change-Id: Icc3ca8458eed4711f25514ac71aa0e6b413ed281
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1921797
Auto-Submit: Dan Elphick <delphick@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65292}

src/utils/utils.cc

@@ -133,8 +133,6 @@ void StrNCpy(Vector<char> dest, const char* src, size_t n) {
   base::OS::StrNCpy(dest.begin(), dest.length(), src, n);
 }
 
-void Flush(FILE* out) { fflush(out); }
-
 char* ReadLine(const char* prompt) {
   char* result = nullptr;
   char line_buf[256];
@@ -229,18 +227,6 @@ std::string VectorToString(const std::vector<char>& chars) {
   return std::string(chars.begin(), chars.end());
 }
 
-}  // namespace
-
-std::string ReadFile(const char* filename, bool* exists, bool verbose) {
-  std::vector<char> result = ReadCharsFromFile(filename, exists, verbose);
-  return VectorToString(result);
-}
-
-std::string ReadFile(FILE* file, bool* exists, bool verbose) {
-  std::vector<char> result = ReadCharsFromFile(file, exists, verbose, "");
-  return VectorToString(result);
-}
-
 int WriteCharsToFile(const char* str, int size, FILE* f) {
   int total = 0;
   while (total < size) {
@@ -254,17 +240,16 @@ int WriteCharsToFile(const char* str, int size, FILE* f) {
   return total;
 }
 
-int AppendChars(const char* filename, const char* str, int size, bool verbose) {
-  FILE* f = base::OS::FOpen(filename, "ab");
-  if (f == nullptr) {
-    if (verbose) {
-      base::OS::PrintError("Cannot open file %s for writing.\n", filename);
-    }
-    return 0;
-  }
-  int written = WriteCharsToFile(str, size, f);
-  fclose(f);
-  return written;
+}  // namespace
+
+std::string ReadFile(const char* filename, bool* exists, bool verbose) {
+  std::vector<char> result = ReadCharsFromFile(filename, exists, verbose);
+  return VectorToString(result);
+}
+
+std::string ReadFile(FILE* file, bool* exists, bool verbose) {
+  std::vector<char> result = ReadCharsFromFile(file, exists, verbose, "");
+  return VectorToString(result);
 }
 
 int WriteChars(const char* filename, const char* str, int size, bool verbose) {

src/utils/utils.h

@@ -574,20 +574,10 @@ V8_EXPORT_PRIVATE int PRINTF_FORMAT(2, 0)
 
 void StrNCpy(Vector<char> dest, const char* src, size_t n);
 
-// Our version of fflush.
-void Flush(FILE* out);
-
-inline void Flush() { Flush(stdout); }
-
 // Read a line of characters after printing the prompt to stdout. The resulting
 // char* needs to be disposed off with DeleteArray by the caller.
 char* ReadLine(const char* prompt);
 
-// Append size chars from str to the file given by filename.
-// The file is overwritten. Returns the number of chars written.
-int AppendChars(const char* filename, const char* str, int size,
-                bool verbose = true);
-
 // Write size chars from str to the file given by filename.
 // The file is overwritten. Returns the number of chars written.
 int WriteChars(const char* filename, const char* str, int size,
@@ -598,13 +588,6 @@ int WriteChars(const char* filename, const char* str, int size,
 int WriteBytes(const char* filename, const byte* bytes, int size,
                bool verbose = true);
 
-// Write the C code
-// const char* <varname> = "<str>";
-// const int <varname>_len = <len>;
-// to the file given by filename. Only the first len chars are written.
-int WriteAsCFile(const char* filename, const char* varname, const char* str,
-                 int size, bool verbose = true);
-
 // Simple support to read a file into std::string.
 // On return, *exits tells whether the file existed.
 V8_EXPORT_PRIVATE std::string ReadFile(const char* filename, bool* exists,