Fix wrong type on std::unique_ptr

Type was a char but should be a char[]

BUG=909692

Change-Id: I2151ab95a0ec0bbefd913f32de1b3e4d51cce6f8
Reviewed-on: https://chromium-review.googlesource.com/c/1354058Reviewed-by: Ryan Sleevi <rsleevi@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611694}

net/tools/dump_cache/dump_files.cc

@@ -296,7 +296,7 @@ bool CacheDumper::HexDump(disk_cache::CacheAddr addr, std::string* out) {
     return false;
 
   size_t size = address.num_blocks() * address.BlockSize();
-  std::unique_ptr<char> buffer(new char[size]);
+  std::unique_ptr<char[]> buffer(new char[size]);
 
   size_t offset = address.start_block() * address.BlockSize() +
                   disk_cache::kBlockHeaderSize;