IndexedDB: Convert decoding functions to pass StringPieces vs. pointers

content/browser/indexed_db/leveldb/leveldb_slice.h

Index: content/browser/indexed_db/leveldb/leveldb_slice.h
diff --git a/content/browser/indexed_db/leveldb/leveldb_slice.h b/content/browser/indexed_db/leveldb/leveldb_slice.h
index 302c0b6b8ca47a0e51127fc0ed638dde4eabbf6e..cb38bec143bbc16b38aa84f475029d0b1b578e83 100644
--- a/content/browser/indexed_db/leveldb/leveldb_slice.h
+++ b/content/browser/indexed_db/leveldb/leveldb_slice.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/logging.h"
+#include "base/strings/string_piece.h"
 
 namespace content {
 
@@ -22,11 +23,20 @@ class LevelDBSlice {
     DCHECK_GE(end_, begin_);
   }
 
+  explicit LevelDBSlice(const std::string& v)
+      : begin_(v.data()), end_(v.data() + v.size()) {
+    DCHECK_GE(end_, begin_);
+  }
+
   ~LevelDBSlice() {}
 
   const char* begin() const { return begin_; }
   const char* end() const { return end_; }
 
+  base::StringPiece AsStringPiece() const {
+    return base::StringPiece(begin_, end_ - begin_);
+  }
+
  private:
   const char* begin_;
   const char* end_;