Scanner / Unicode decoding: use size_t instead of unsigned.

src/scanner.h

Index: src/scanner.h
diff --git a/src/scanner.h b/src/scanner.h
index 8537c5308c9f73e8dbf2f5f97e8188f195d531cc..86a0098f86c0b4c97b4958148c4f6d27f04ce9b8 100644
--- a/src/scanner.h
+++ b/src/scanner.h
@@ -67,15 +67,14 @@ class Utf16CharacterStream {
 
   // Return the current position in the code unit stream.
   // Starts at zero.
-  inline unsigned pos() const { return pos_; }
+  inline size_t pos() const { return pos_; }
 
   // Skips forward past the next code_unit_count UTF-16 code units
   // in the input, or until the end of input if that comes sooner.
   // Returns the number of code units actually skipped. If less
   // than code_unit_count,
-  inline unsigned SeekForward(unsigned code_unit_count) {
-    unsigned buffered_chars =
-        static_cast<unsigned>(buffer_end_ - buffer_cursor_);
+  inline size_t SeekForward(size_t code_unit_count) {
+    size_t buffered_chars = buffer_end_ - buffer_cursor_;
     if (code_unit_count <= buffered_chars) {
       buffer_cursor_ += code_unit_count;
       pos_ += code_unit_count;
@@ -98,11 +97,11 @@ class Utf16CharacterStream {
   // is at or after the end of the input, return false. If there
   // are more code_units available, return true.
   virtual bool ReadBlock() = 0;
-  virtual unsigned SlowSeekForward(unsigned code_unit_count) = 0;
+  virtual size_t SlowSeekForward(size_t code_unit_count) = 0;
 
   const uint16_t* buffer_cursor_;
   const uint16_t* buffer_end_;
-  unsigned pos_;
+  size_t pos_;
 };
 
 
@@ -697,7 +696,7 @@ class Scanner {
 
   // Return the current source position.
   int source_pos() {
-    return source_->pos() - kCharacterLookaheadBufferSize;
+    return static_cast<int>(source_->pos()) - kCharacterLookaheadBufferSize;
   }
 
   UnicodeCache* unicode_cache_;