Streaming API: detect UTF-8 BOM.

src/scanner-character-streams.h

Index: src/scanner-character-streams.h
diff --git a/src/scanner-character-streams.h b/src/scanner-character-streams.h
index ff22de59f72a370d93abe1f67eb154eb6b2c1874..ac399f67200bb11e6d26328dd8fefa8266281080 100644
--- a/src/scanner-character-streams.h
+++ b/src/scanner-character-streams.h
@@ -87,7 +87,8 @@ class ExternalStreamingStream : public BufferedUtf16CharacterStream {
         current_data_(NULL),
         current_data_offset_(0),
         current_data_length_(0),
-        utf8_split_char_buffer_length_(0) {}
+        utf8_split_char_buffer_length_(0),
+        first_chunk_(true) {}
 
   virtual ~ExternalStreamingStream() { delete[] current_data_; }
 
@@ -113,6 +114,7 @@ class ExternalStreamingStream : public BufferedUtf16CharacterStream {
   // For converting UTF-8 characters which are split across two data chunks.
   uint8_t utf8_split_char_buffer_[4];
   unsigned utf8_split_char_buffer_length_;
+  bool first_chunk_;
 };