Add support for fallback content for the frame. This includes main and subframes.

content/common/throttling_url_loader.cc

Index: content/common/throttling_url_loader.cc
diff --git a/content/common/throttling_url_loader.cc b/content/common/throttling_url_loader.cc
index 7fa5b73b20d8e27d1866fcb85b425f52556eb5a5..ddc11010f2615aa83a5a615b2240b5bf8b0a45f8 100644
--- a/content/common/throttling_url_loader.cc
+++ b/content/common/throttling_url_loader.cc
@@ -93,7 +93,7 @@ void ThrottlingURLLoader::FollowRedirect() {
 
 void ThrottlingURLLoader::SetPriority(net::RequestPriority priority,
                                       int32_t intra_priority_value) {
-  if (!url_loader_ && !cancelled_by_throttle_) {
+  if (!url_loader_ && !loader_cancelled_) {
     DCHECK_EQ(DEFERRED_START, deferred_stage_);
     priority_info_ =
         base::MakeUnique<PriorityInfo>(priority, intra_priority_value);
@@ -103,6 +103,12 @@ void ThrottlingURLLoader::SetPriority(net::RequestPriority priority,
   url_loader_->SetPriority(priority, intra_priority_value);
 }
 
+void ThrottlingURLLoader::DisconnectClient() {
+  client_binding_.Close();
+  url_loader_ = nullptr;
+  loader_cancelled_ = true;
+}
+
 ThrottlingURLLoader::ThrottlingURLLoader(
     std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
     mojom::URLLoaderClient* client,
@@ -128,13 +134,13 @@ void ThrottlingURLLoader::Start(
     const ResourceRequest& url_request,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   if (throttle_) {
     bool deferred = false;
     throttle_->WillStartRequest(url_request.url, url_request.load_flags,
                                 url_request.resource_type, &deferred);
-    if (cancelled_by_throttle_)
+    if (loader_cancelled_)
       return;
 
     if (deferred) {
@@ -187,12 +193,12 @@ void ThrottlingURLLoader::OnReceiveResponse(
     const base::Optional<net::SSLInfo>& ssl_info,
     mojom::DownloadedTempFilePtr downloaded_file) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   if (throttle_) {
     bool deferred = false;
     throttle_->WillProcessResponse(&deferred);
-    if (cancelled_by_throttle_)
+    if (loader_cancelled_)
       return;
 
     if (deferred) {
@@ -212,12 +218,12 @@ void ThrottlingURLLoader::OnReceiveRedirect(
     const net::RedirectInfo& redirect_info,
     const ResourceResponseHead& response_head) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   if (throttle_) {
     bool deferred = false;
     throttle_->WillRedirectRequest(redirect_info, &deferred);
-    if (cancelled_by_throttle_)
+    if (loader_cancelled_)
       return;
 
     if (deferred) {
@@ -235,7 +241,7 @@ void ThrottlingURLLoader::OnReceiveRedirect(
 void ThrottlingURLLoader::OnDataDownloaded(int64_t data_len,
                                            int64_t encoded_data_len) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   forwarding_client_->OnDataDownloaded(data_len, encoded_data_len);
 }
@@ -245,7 +251,7 @@ void ThrottlingURLLoader::OnUploadProgress(
     int64_t total_size,
     OnUploadProgressCallback ack_callback) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   forwarding_client_->OnUploadProgress(current_position, total_size,
                                        std::move(ack_callback));
@@ -254,14 +260,14 @@ void ThrottlingURLLoader::OnUploadProgress(
 void ThrottlingURLLoader::OnReceiveCachedMetadata(
     const std::vector<uint8_t>& data) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   forwarding_client_->OnReceiveCachedMetadata(data);
 }
 
 void ThrottlingURLLoader::OnTransferSizeUpdated(int32_t transfer_size_diff) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   forwarding_client_->OnTransferSizeUpdated(transfer_size_diff);
 }
@@ -269,7 +275,7 @@ void ThrottlingURLLoader::OnTransferSizeUpdated(int32_t transfer_size_diff) {
 void ThrottlingURLLoader::OnStartLoadingResponseBody(
     mojo::ScopedDataPipeConsumerHandle body) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   forwarding_client_->OnStartLoadingResponseBody(std::move(body));
 }
@@ -277,7 +283,7 @@ void ThrottlingURLLoader::OnStartLoadingResponseBody(
 void ThrottlingURLLoader::OnComplete(
     const ResourceRequestCompletionStatus& status) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
-  DCHECK(!cancelled_by_throttle_);
+  DCHECK(!loader_cancelled_);
 
   forwarding_client_->OnComplete(status);
 }
@@ -285,24 +291,20 @@ void ThrottlingURLLoader::OnComplete(
 void ThrottlingURLLoader::CancelWithError(int error_code) {
   // TODO(yzshen): Support a mode that cancellation also deletes the disk cache
   // entry.
-  if (cancelled_by_throttle_)
+  if (loader_cancelled_)
     return;
 
-  cancelled_by_throttle_ = true;
-
   ResourceRequestCompletionStatus request_complete_data;
   request_complete_data.error_code = error_code;
   request_complete_data.completion_time = base::TimeTicks::Now();
 
   deferred_stage_ = DEFERRED_NONE;
-  client_binding_.Close();
-  url_loader_ = nullptr;
-
+  DisconnectClient();
   forwarding_client_->OnComplete(request_complete_data);
 }
 
 void ThrottlingURLLoader::Resume() {
-  if (cancelled_by_throttle_ || deferred_stage_ == DEFERRED_NONE)
+  if (loader_cancelled_ || deferred_stage_ == DEFERRED_NONE)
     return;
 
   switch (deferred_stage_) {