Remove dead code in line_ending.{h,cc}

* Remove the CString-version of NormalizeLineEndingsToCRLF()
  It's not used.

* Remove CStringBuffer.
  Only the CString NormalizeLineEndingsToCRLF() used it.

* Fold VectorCharAppendBuffer into InternalNormalizeLineEndingsToCRLF()
  OutputBuffer abstraction isn't necessary due to the removal of
  CStringBuffer, and InternalNormalizeLineEndingsToCRLF() is the only
  user of OutputBuffer.

* Wrap InternalNormalizeLineEndingsToCRLF() with OS_WIN.
  It is used only on Windows.

This CL has no behavior changes.

Change-Id: I01d6177601f8be5fd5137f1554e7824080422d8f
Reviewed-on: https://chromium-review.googlesource.com/1072222Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561776}

third_party/blink/renderer/platform/text/line_ending.cc

@@ -41,55 +41,6 @@
 namespace blink {
 namespace {
 
-class OutputBuffer {
-  STACK_ALLOCATED();
-  DISALLOW_COPY_AND_ASSIGN(OutputBuffer);
-
- public:
-  OutputBuffer() = default;
-  virtual char* Allocate(size_t) = 0;
-  virtual void Copy(const CString&) = 0;
-  virtual ~OutputBuffer() = default;
-};
-
-class CStringBuffer final : public OutputBuffer {
- public:
-  CStringBuffer(CString& buffer) : buffer_(buffer) {}
-  ~CStringBuffer() override = default;
-
-  char* Allocate(size_t size) override {
-    char* ptr;
-    buffer_ = CString::CreateUninitialized(size, ptr);
-    return ptr;
-  }
-
-  void Copy(const CString& source) override { buffer_ = source; }
-
-  const CString& Buffer() const { return buffer_; }
-
- private:
-  CString buffer_;
-};
-
-class VectorCharAppendBuffer final : public OutputBuffer {
- public:
-  VectorCharAppendBuffer(Vector<char>& buffer) : buffer_(buffer) {}
-  ~VectorCharAppendBuffer() override = default;
-
-  char* Allocate(size_t size) override {
-    size_t old_size = buffer_.size();
-    buffer_.Grow(old_size + size);
-    return buffer_.data() + old_size;
-  }
-
-  void Copy(const CString& source) override {
-    buffer_.Append(source.data(), source.length());
-  }
-
- private:
-  Vector<char>& buffer_;
-};
-
 template <typename CharType>
 size_t RequiredSizeForCRLF(const CharType* data, size_t length) {
   size_t new_len = 0;
@@ -138,19 +89,24 @@ void NormalizeToCRLF(const CharType* src, size_t src_length, CharType* q) {
   }
 }
 
+#if defined(OS_WIN)
 void InternalNormalizeLineEndingsToCRLF(const CString& from,
-                                        OutputBuffer& buffer) {
+                                        Vector<char>& buffer) {
   size_t new_len = RequiredSizeForCRLF(from.data(), from.length());
   if (new_len < from.length())
     return;
 
   if (new_len == from.length()) {
-    buffer.Copy(from);
+    buffer.Append(from.data(), from.length());
     return;
   }
 
-  NormalizeToCRLF(from.data(), from.length(), buffer.Allocate(new_len));
+  size_t old_buffer_size = buffer.size();
+  buffer.Grow(old_buffer_size + new_len);
+  char* write_position = buffer.data() + old_buffer_size;
+  NormalizeToCRLF(from.data(), from.length(), write_position);
 }
+#endif  // defined(OS_WIN)
 
 }  // namespace
 
@@ -203,15 +159,6 @@ void NormalizeLineEndingsToLF(const CString& from, Vector<char>& result) {
   }
 }
 
-CString NormalizeLineEndingsToCRLF(const CString& from) {
-  if (!from.length())
-    return from;
-  CString result;
-  CStringBuffer buffer(result);
-  InternalNormalizeLineEndingsToCRLF(from, buffer);
-  return buffer.Buffer();
-}
-
 String NormalizeLineEndingsToCRLF(const String& src) {
   size_t length = src.length();
   if (length == 0)
@@ -234,8 +181,7 @@ String NormalizeLineEndingsToCRLF(const String& src) {
 
 void NormalizeLineEndingsToNative(const CString& from, Vector<char>& result) {
 #if defined(OS_WIN)
-  VectorCharAppendBuffer buffer(result);
-  InternalNormalizeLineEndingsToCRLF(from, buffer);
+  InternalNormalizeLineEndingsToCRLF(from, result);
 #else
   NormalizeLineEndingsToLF(from, result);
 #endif

third_party/blink/renderer/platform/text/line_ending.h

@@ -39,7 +39,6 @@
 namespace blink {
 
 // Normalize all line-endings in the given string to CRLF.
-PLATFORM_EXPORT CString NormalizeLineEndingsToCRLF(const CString& from);
 PLATFORM_EXPORT String NormalizeLineEndingsToCRLF(const String& from);
 
 // Normalize all line-endings in the given string to LF and append the result to