DevTools: report loadingFailed event for nav requests cancelled because of 204

Bug: 840962
Change-Id: I7df6c302cd13a2a0d8085b26cff4e2fa34f6aca0
Reviewed-on: https://chromium-review.googlesource.com/1054358Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557898}

content/browser/frame_host/navigation_request.cc

@@ -1003,8 +1003,6 @@ void NavigationRequest::OnRequestFailed(
     bool has_stale_copy_in_cache,
     int net_error,
     const base::Optional<net::SSLInfo>& ssl_info) {
-  RenderFrameDevToolsAgentHost::OnNavigationRequestFailed(*this, net_error);
-
   NavigationRequest::OnRequestFailedInternal(has_stale_copy_in_cache, net_error,
                                              ssl_info, false, base::nullopt);
 }
@@ -1018,6 +1016,8 @@ void NavigationRequest::OnRequestFailedInternal(
   DCHECK(state_ == STARTED || state_ == RESPONSE_STARTED);
   DCHECK(!(net_error == net::ERR_ABORTED && error_page_content.has_value()));
 
+  RenderFrameDevToolsAgentHost::OnNavigationRequestFailed(*this, net_error);
+
   // TODO(https://crbug.com/757633): Check that ssl_info.has_value() if
   // net_error is a certificate error.
   TRACE_EVENT_ASYNC_STEP_INTO1("navigation", "NavigationRequest", this,

third_party/WebKit/LayoutTests/http/tests/inspector-protocol/network/navigation-204-loading-failed-expected.txt

+Tests that navigation request resulting in HTTP 204 is reported as failed.
+responseReceived: http://127.0.0.1:8000/inspector-protocol/page/resources/http204.php 204 No Content
+loadingFailed: canceled = true
+

third_party/WebKit/LayoutTests/http/tests/inspector-protocol/network/navigation-204-loading-failed.js

+(async function(testRunner) {
+  var {page, session, dp} = await testRunner.startBlank(
+      `Tests that navigation request resulting in HTTP 204 is reported as failed.`);
+
+  dp.Network.enable();
+  dp.Page.enable();
+  dp.Network.onResponseReceived(event => {
+    const response = event.params.response;
+    testRunner.log(`responseReceived: ${response.url} ${response.status} ${response.statusText}`);
+  });
+  dp.Network.onLoadingFailed(event => {
+    const params = event.params;
+    testRunner.log(`loadingFailed: canceled = ${params.canceled}`);
+    testRunner.completeTest();
+  });
+  page.navigate('http://127.0.0.1:8000/inspector-protocol/page/resources/http204.php');
+})
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