Make URLFetcherCore::ReleaseRequest() release |buffer_|.

net/url_request/url_fetcher_core.cc

Index: net/url_request/url_fetcher_core.cc
diff --git a/net/url_request/url_fetcher_core.cc b/net/url_request/url_fetcher_core.cc
index 2a7a4d2899830a41287eab8107b5f2f462ece75d..25b60086d8f2732a2b84d47987720dd6d7ceced5 100644
--- a/net/url_request/url_fetcher_core.cc
+++ b/net/url_request/url_fetcher_core.cc
@@ -82,7 +82,6 @@ URLFetcherCore::URLFetcherCore(URLFetcher* fetcher,
       delegate_task_runner_(base::SequencedTaskRunnerHandle::Get()),
       load_flags_(LOAD_NORMAL),
       response_code_(URLFetcher::RESPONSE_CODE_INVALID),
-      buffer_(new IOBuffer(kBufferSize)),
       url_request_data_key_(NULL),
       was_fetched_via_proxy_(false),
       was_cached_(false),
@@ -457,6 +456,7 @@ void URLFetcherCore::OnReadCompleted(URLRequest* request,
     url_throttler_entry_ = throttler_manager->RegisterRequestUrl(url_);
 
   while (bytes_read > 0) {
+    DCHECK(buffer_);
     current_response_bytes_ += bytes_read;
     InformDelegateDownloadProgress();
 
@@ -816,6 +816,7 @@ void URLFetcherCore::ReleaseRequest() {
   request_context_getter_->RemoveObserver(this);
   upload_progress_checker_timer_.reset();
   request_.reset();
+  buffer_ = nullptr;
   g_registry.Get().RemoveURLFetcherCore(this);
 }
 
@@ -888,8 +889,11 @@ void URLFetcherCore::ReadResponse() {
   // completed immediately, without trying to read any data back (all we care
   // about is the response code and headers, which we already have).
   int bytes_read = 0;
-  if (request_type_ != URLFetcher::HEAD)
+  if (request_type_ != URLFetcher::HEAD) {
+    if (!buffer_)
+      buffer_ = new IOBuffer(kBufferSize);

[mmenke, 2017/01/25 16:32:16]

Just do this unconditionally in OnResponseStarted, where we know it's nullptr
(Head requests are sufficiently rare that I don't think we care about them, and
we'll clean it up immediately in OnReadCompleted, anyways - actually, I think
the HEAD check would make more sense in there, too).

[xunjieli, 2017/01/25 16:41:53]

Done.

     bytes_read = request_->Read(buffer_.get(), kBufferSize);
+  }
 
   OnReadCompleted(request_.get(), bytes_read);
 }