SignedExchangeHandler: Populate load timings

This patch makes SignedExchangeHandler populate the minimal set of
timing info for the HTTP exchange response, so that devtools' network
timeline will show reasonable values.

Bug: 803774
Change-Id: Ida0d34f7bab86f5ff674b776fe5fca511111c87c
Reviewed-on: https://chromium-review.googlesource.com/967632Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544010}

content/browser/web_package/signed_exchange_handler.cc

@@ -326,6 +326,15 @@ void SignedExchangeHandler::OnCertVerifyComplete(int result) {
   response_head.headers->GetMimeTypeAndCharset(&response_head.mime_type,
                                                &response_head.charset);
 
+  // TODO(https://crbug.com/803774): Resource timing for signed exchange
+  // loading is not speced yet. https://github.com/WICG/webpackage/issues/156
+  response_head.load_timing.request_start_time = base::Time::Now();
+  base::TimeTicks now(base::TimeTicks::Now());
+  response_head.load_timing.request_start = now;
+  response_head.load_timing.send_start = now;
+  response_head.load_timing.send_end = now;
+  response_head.load_timing.receive_headers_end = now;
+
   std::string mi_header_value;
   if (!response_head.headers->EnumerateHeader(nullptr, kMiHeader,
                                               &mi_header_value)) {

content/browser/web_package/signed_exchange_handler_unittest.cc

@@ -197,6 +197,11 @@ TEST_P(SignedExchangeHandlerTest, Simple) {
   EXPECT_EQ(200, resource_response().headers->response_code());
   EXPECT_EQ("text/html", resource_response().mime_type);
   EXPECT_EQ("utf-8", resource_response().charset);
+  EXPECT_FALSE(resource_response().load_timing.request_start_time.is_null());
+  EXPECT_FALSE(resource_response().load_timing.request_start.is_null());
+  EXPECT_FALSE(resource_response().load_timing.send_start.is_null());
+  EXPECT_FALSE(resource_response().load_timing.send_end.is_null());
+  EXPECT_FALSE(resource_response().load_timing.receive_headers_end.is_null());
 
   std::string payload;
   int rv = ReadPayloadStream(&payload);