AppCache: Add checks around resource and master entry fetches

Bug: 989611
Change-Id: I44bc45661e194f78f5cfa90d59e0e78c8b20c278
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2005670
Auto-Submit: Chase Phillips <cmp@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Commit-Queue: Chase Phillips <cmp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734172}

content/browser/appcache/appcache_update_job.cc

@@ -681,6 +681,10 @@ void AppCacheUpdateJob::HandleResourceFetchCompleted(URLFetcher* url_fetcher,
   std::unique_ptr<URLFetcher> entry_fetcher = std::move(it->second);
   pending_url_fetches_.erase(it);
 
+  // URLFetcher should only trigger this for resources, even if those entries
+  // happen to be manifest entries.
+  DCHECK_EQ(entry_fetcher->fetch_type(), URLFetcher::FetchType::kResource);
+
   NotifyAllProgress(url);
   ++url_fetches_completed_;
 
@@ -805,6 +809,11 @@ void AppCacheUpdateJob::HandleNewMasterEntryFetchCompleted(
   std::unique_ptr<URLFetcher> entry_fetcher = std::move(it->second);
   master_entry_fetches_.erase(it);
 
+  // URLFetcher triggers this function, so we verify here that the fetch type
+  // in URLFetcher is what we expect: kNewMasterEntry.
+  DCHECK_EQ(entry_fetcher->fetch_type(),
+            URLFetcher::FetchType::kNewMasterEntry);
+
   ++master_entries_completed_;
 
   int response_code = net_error == net::OK ? request->GetResponseCode() : -1;

content/browser/appcache/appcache_update_url_fetcher.cc

@@ -146,6 +146,8 @@ void AppCacheUpdateJob::URLFetcher::AddConditionalHeaders(
     const net::HttpResponseHeaders* headers) {
   DCHECK(request_);
   DCHECK(headers);
+  DCHECK_NE(fetch_type_, FetchType::kNewMasterEntry);
+
   net::HttpRequestHeaders extra_headers;
 
   // Add If-Modified-Since header if response info has Last-Modified header.