Fix a bunch of clang warnings/errors.

net/disk_cache/entry_impl.cc

Index: net/disk_cache/entry_impl.cc
diff --git a/net/disk_cache/entry_impl.cc b/net/disk_cache/entry_impl.cc
index 5b65344c2354a84ae2931add0f19ede658604723..8d9fab60cf5ced0c1b79bec43c89d75d5d02aad1 100644
--- a/net/disk_cache/entry_impl.cc
+++ b/net/disk_cache/entry_impl.cc
@@ -64,19 +64,6 @@ void SyncCallback::Discard() {
   OnFileIOComplete(0);
 }
 
-// Clears buffer before offset and after valid_len, knowing that the size of
-// buffer is kMaxBlockSize.
-void ClearInvalidData(char* buffer, int offset, int valid_len) {
-  DCHECK_GE(offset, 0);
-  DCHECK_GE(valid_len, 0);
-  DCHECK(disk_cache::kMaxBlockSize >= offset + valid_len);
-  if (offset)
-    memset(buffer, 0, offset);
-  int end = disk_cache::kMaxBlockSize - offset - valid_len;
-  if (end)
-    memset(buffer + offset + valid_len, 0, end);
-}
-
 const int kMaxBufferSize = 1024 * 1024;  // 1 MB.
 
 }  // namespace