[net] Better StopCaching() handling for HttpCache::Transaction.

net/http/http_transaction_test_util.cc

Index: net/http/http_transaction_test_util.cc
diff --git a/net/http/http_transaction_test_util.cc b/net/http/http_transaction_test_util.cc
index 1b2960bb250e12fff7d9f10cc8fd4705b0bc6606..ff5ef4f36a3ba72a9829efdf9828e1b992f6a902 100644
--- a/net/http/http_transaction_test_util.cc
+++ b/net/http/http_transaction_test_util.cc
@@ -49,7 +49,6 @@ const MockTransaction kSimpleGET_Transaction = {
     nullptr,
     nullptr,
     0,
-    0,
     OK};
 
 const MockTransaction kSimplePOST_Transaction = {
@@ -66,7 +65,6 @@ const MockTransaction kSimplePOST_Transaction = {
     nullptr,
     nullptr,
     0,
-    0,
     OK};
 
 const MockTransaction kTypicalGET_Transaction = {
@@ -84,7 +82,6 @@ const MockTransaction kTypicalGET_Transaction = {
     nullptr,
     nullptr,
     0,
-    0,
     OK};
 
 const MockTransaction kETagGET_Transaction = {
@@ -102,7 +99,6 @@ const MockTransaction kETagGET_Transaction = {
     nullptr,
     nullptr,
     0,
-    0,
     OK};
 
 const MockTransaction kRangeGET_Transaction = {
@@ -119,7 +115,6 @@ const MockTransaction kRangeGET_Transaction = {
     nullptr,
     nullptr,
     0,
-    0,
     OK};
 
 static const MockTransaction* const kBuiltinMockTransactions[] = {
@@ -141,7 +136,7 @@ const MockTransaction* FindMockTransaction(const GURL& url) {
     if (url == GURL(kBuiltinMockTransactions[i]->url))
       return kBuiltinMockTransactions[i];
   }
-  return NULL;
+  return nullptr;
 }
 
 void AddMockTransaction(const MockTransaction* trans) {
@@ -236,15 +231,16 @@ void TestTransactionConsumer::OnIOComplete(int result) {
 
 MockNetworkTransaction::MockNetworkTransaction(RequestPriority priority,
                                                MockNetworkLayer* factory)
-    : request_(NULL),
+    : request_(nullptr),
       data_cursor_(0),
+      content_length_(0),
       priority_(priority),
-      websocket_handshake_stream_create_helper_(NULL),
+      read_handler_(nullptr),
+      websocket_handshake_stream_create_helper_(nullptr),
       transaction_factory_(factory->AsWeakPtr()),
       received_bytes_(0),
       socket_log_id_(NetLog::Source::kInvalidId),
-      weak_factory_(this) {
-}
+      weak_factory_(this) {}
 
 MockNetworkTransaction::~MockNetworkTransaction() {}
 
@@ -297,16 +293,22 @@ bool MockNetworkTransaction::IsReadyToRestartForAuth() {
       status_line.find(" 407 ") != std::string::npos;
 }
 
-int MockNetworkTransaction::Read(IOBuffer* buf,
+int MockNetworkTransaction::Read(net::IOBuffer* buf,
                                  int buf_len,
                                  const CompletionCallback& callback) {
-  int data_len = static_cast<int>(data_.size());
-  int num = std::min(buf_len, data_len - data_cursor_);
-  if (test_mode_ & TEST_MODE_SLOW_READ)
-    num = std::min(num, 1);
-  if (num) {
-    memcpy(buf->data(), data_.data() + data_cursor_, num);
+  int num = 0;
+  if (read_handler_) {
+    num = (*read_handler_)(content_length_, data_cursor_, buf, buf_len);
     data_cursor_ += num;
+  } else {
+    int data_len = static_cast<int>(data_.size());
+    num = std::min(static_cast<int64>(buf_len), data_len - data_cursor_);
+    if (test_mode_ & TEST_MODE_SLOW_READ)
+      num = std::min(num, 1);
+    if (num) {
+      memcpy(buf->data(), data_.data() + data_cursor_, num);
+      data_cursor_ += num;
+    }
   }
   if (test_mode_ & TEST_MODE_SYNC_NET_READ)
     return num;
@@ -390,6 +392,13 @@ int MockNetworkTransaction::StartInternal(const HttpRequestInfo* request,
   if (!t)
     return ERR_FAILED;
 
+  if (!before_network_start_callback_.is_null()) {
+    bool defer = false;
+    before_network_start_callback_.Run(&defer);
+    if (defer)
+      return net::ERR_IO_PENDING;
+  }
+
   test_mode_ = t->test_mode;
 
   // Return immediately if we're returning an error.
@@ -406,6 +415,8 @@ int MockNetworkTransaction::StartInternal(const HttpRequestInfo* request,
   received_bytes_ = resp_status.size() + resp_headers.size() + resp_data.size();
   if (t->handler)
     (t->handler)(request, &resp_status, &resp_headers, &resp_data);
+  if (t->read_handler)
+    read_handler_ = t->read_handler;
 
   std::string header_data = base::StringPrintf(
       "%s\n%s\n", resp_status.c_str(), resp_headers.c_str());
@@ -428,6 +439,7 @@ int MockNetworkTransaction::StartInternal(const HttpRequestInfo* request,
   response_.ssl_info.cert_status = t->cert_status;
   response_.ssl_info.connection_status = t->ssl_connection_status;
   data_ = resp_data;
+  content_length_ = response_.headers->GetContentLength();
 
   if (net_log.net_log())
     socket_log_id_ = net_log.net_log()->NextID();
@@ -444,6 +456,7 @@ int MockNetworkTransaction::StartInternal(const HttpRequestInfo* request,
 
 void MockNetworkTransaction::SetBeforeNetworkStartCallback(
     const BeforeNetworkStartCallback& callback) {
+  before_network_start_callback_ = callback;
 }
 
 void MockNetworkTransaction::SetBeforeProxyHeadersSentCallback(