Add UMA to record priority keyed completion times of requests

Bug: 741924
Change-Id: Ifd3355657a30a0e40d73517fbf79dca41d992512
Reviewed-on: https://chromium-review.googlesource.com/568716
Commit-Queue: Devdeep Ray <devdeepray@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486563}

net/url_request/url_request_http_job.cc

@@ -15,11 +15,13 @@
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/metrics/field_trial.h"
+#include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/rand_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
@@ -1509,6 +1511,10 @@ void URLRequestHttpJob::RecordPerfHistograms(CompletionCause reason) {
   UMA_HISTOGRAM_TIMES("Net.HttpJob.TotalTime", total_time);
 
   if (reason == FINISHED) {
+    UmaHistogramTimes(
+        base::StringPrintf("Net.HttpJob.TotalTimeSuccess.Priority%d",
+                           request()->priority()),
+        total_time);
     UMA_HISTOGRAM_TIMES("Net.HttpJob.TotalTimeSuccess", total_time);
   } else {
     UMA_HISTOGRAM_TIMES("Net.HttpJob.TotalTimeCancel", total_time);

net/url_request/url_request_http_job_unittest.cc

@@ -16,6 +16,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/run_loop.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/test/histogram_tester.h"
 #include "net/base/auth.h"
@@ -813,6 +814,40 @@ TEST_F(URLRequestHttpJobWithMockSocketsTest,
   histograms.ExpectTotalCount("Net.HttpTimeToFirstByte", 0);
 }
 
+TEST_F(URLRequestHttpJobWithMockSocketsTest,
+       TestHttpJobSuccessPriorityKeyedTotalTime) {
+  base::HistogramTester histograms;
+
+  for (int priority = 0; priority < net::NUM_PRIORITIES; ++priority) {
+    for (int request_index = 0; request_index <= priority; ++request_index) {
+      MockWrite writes[] = {MockWrite(kSimpleGetMockWrite)};
+      MockRead reads[] = {MockRead("HTTP/1.1 200 OK\r\n"
+                                   "Content-Length: 12\r\n\r\n"),
+                          MockRead("Test Content")};
+
+      StaticSocketDataProvider socket_data(reads, arraysize(reads), writes,
+                                           arraysize(writes));
+      socket_factory_.AddSocketDataProvider(&socket_data);
+
+      TestDelegate delegate;
+      std::unique_ptr<URLRequest> request =
+          context_->CreateRequest(GURL("http://www.example.com/"),
+                                  static_cast<net::RequestPriority>(priority),
+                                  &delegate, TRAFFIC_ANNOTATION_FOR_TESTS);
+
+      request->Start();
+      base::RunLoop().Run();
+      EXPECT_THAT(delegate.request_status(), IsOk());
+    }
+  }
+
+  for (int priority = 0; priority < net::NUM_PRIORITIES; ++priority) {
+    histograms.ExpectTotalCount(
+        "Net.HttpJob.TotalTimeSuccess.Priority" + base::IntToString(priority),
+        priority + 1);
+  }
+}
+
 TEST_F(URLRequestHttpJobTest, TestCancelWhileReadingCookies) {
   DelayedCookieMonster cookie_monster;
   TestURLRequestContext context(true);

tools/metrics/histograms/histograms.xml

@@ -92489,6 +92489,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <affected-histogram name="Net.BidirectionalStream.TimeToSendStart"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="Net.HttpJob.TotalTimeSuccess.Priorities"
+    separator=".">
+  <suffix name="Priority0" label="THROTTLED or MINIMUM_PRIORITY"/>
+  <suffix name="Priority1" label="IDLE"/>
+  <suffix name="Priority2" label="LOWEST or DEFAULT_PRIORITY"/>
+  <suffix name="Priority3" label="LOW"/>
+  <suffix name="Priority4" label="MEDIUM"/>
+  <suffix name="Priority5" label="HIGHEST or MAXIMUM_PRIORITY"/>
+  <affected-histogram name="Net.HttpJob.TotalTimeSuccess"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="Net.QuicClientHelloRejectReasons.QuicIsSecureOrNot"
     separator=".">
   <owner>rch@chromium.org</owner>