Add Browser Task Scheduler Flags

Adds the browser scheduler command line flags as well as exposing it via chrome://flags. Enabling the feature will place the browser in a forced variations group, allowing it to use task scheduler parameters from there. If the variations group is unavailable, then enabling this will still not enable the browser task scheduler BUG=553459,633389 Review-Url: https://codereview.chromium.org/2227343002 Cr-Commit-Position: refs/heads/master@{#411199}
Denger-Network · Aug 11, 2016 · 2ce242f · 2ce242f
1 parent a684684
commit 2ce242f
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Showing 7 changed files with 57 additions and 1 deletion.
diff --git a/base/BUILD.gn b/base/BUILD.gn
@@ -1487,6 +1487,8 @@ static_library("base_static") {
   sources = [
     "base_switches.cc",
     "base_switches.h",
+    "task_scheduler/switches.cc",
+    "task_scheduler/switches.h",
     "win/pe_image.cc",
     "win/pe_image.h",
   ]

diff --git a/base/task_scheduler/switches.cc b/base/task_scheduler/switches.cc
@@ -0,0 +1,12 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/task_scheduler/switches.h"
+
+namespace switches {
+
+const char kDisableBrowserTaskScheduler[] = "disable-browser-task-scheduler";
+const char kEnableBrowserTaskScheduler[] = "enable-browser-task-scheduler";
+
+}  // namespace switches
diff --git a/base/task_scheduler/switches.h b/base/task_scheduler/switches.h
@@ -0,0 +1,15 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_TASK_SCHEDULER_SWITCHES_H_
+#define BASE_TASK_SCHEDULER_SWITCHES_H_
+
+namespace switches {
+
+extern const char kDisableBrowserTaskScheduler[];
+extern const char kEnableBrowserTaskScheduler[];
+
+}  // namespace switches
+
+#endif  // BASE_TASK_SCHEDULER_SWITCHES_H_
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
@@ -13656,6 +13656,18 @@ Please check your email at <ph name="ACCOUNT_EMAIL">$2<ex>jane.doe@gmail.com</ex
         Highly experimental performance mode where cross-site iframes are kept in a separate process from the top document. In this mode, iframes from different third-party sites will be allowed to share a process.
       </message>
 
+      <!-- Browser Task Scheduler -->
+      <message name="IDS_FLAGS_BROWSER_TASK_SCHEDULER_NAME"
+               desc="Name of about:flag option to control the availability of the browser task scheduler."
+               translateable="false">
+        Browser Task Scheduler
+      </message>
+      <message name="IDS_FLAGS_BROWSER_TASK_SCHEDULER_DESCRIPTION"
+               desc="Description of about:flag option to control the availability of the browser task scheduler."
+               translateable="false">
+        Enables the browser task scheduler to dispatch tasks instead of the existing worker pools. The browser task scheduler will only be used if variation parameters are available.
+      </message>
+
       <!-- Windows 8 Metro mode. -->
       <if expr="is_win">
         <message name="IDS_METRO_FLOW_DESCRIPTION"

diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
@@ -22,6 +22,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_scheduler/switches.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
@@ -2044,6 +2045,10 @@ const FeatureEntry kFeatureEntries[] = {
      IDS_FLAGS_QUICK_UNLOCK_PIN_DESCRIPTION, kOsCrOS,
      FEATURE_VALUE_TYPE(features::kQuickUnlockPin)},
 #endif  // defined(OS_CHROMEOS)
+    {"browser-task-scheduler", IDS_FLAGS_BROWSER_TASK_SCHEDULER_NAME,
+     IDS_FLAGS_BROWSER_TASK_SCHEDULER_DESCRIPTION, kOsAll,
+     ENABLE_DISABLE_VALUE_TYPE(switches::kEnableBrowserTaskScheduler,
+                               switches::kDisableBrowserTaskScheduler)},
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in
     // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.

diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
@@ -37,6 +37,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
 #include "base/task_scheduler/scheduler_worker_pool_params.h"
+#include "base/task_scheduler/switches.h"
 #include "base/task_scheduler/task_scheduler.h"
 #include "base/task_scheduler/task_traits.h"
 #include "base/threading/platform_thread.h"
@@ -395,8 +396,15 @@ size_t WorkerPoolIndexForTraits(const base::TaskTraits& traits) {
 void MaybeInitializeTaskScheduler() {
   static constexpr char kFieldTrialName[] = "BrowserScheduler";
   std::map<std::string, std::string> variation_params;
-  if (!variations::GetVariationParams(kFieldTrialName, &variation_params))
+  if (!variations::GetVariationParams(kFieldTrialName, &variation_params)) {
+    DCHECK(!base::CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kEnableBrowserTaskScheduler))
+        << "The Browser Task Scheduler remains disabled with "
+        << switches::kEnableBrowserTaskScheduler
+        << " because there is no available variation param for this build or "
+           " the task scheduler is disabled in chrome://flags.";
     return;
+  }
 
   using ThreadPriority = base::ThreadPriority;
   using IORestriction = base::SchedulerWorkerPoolParams::IORestriction;

diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
@@ -83237,6 +83237,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="-474322576" label="disable-quick-unlock-pin"/>
   <int value="-462205750" label="enable-service-worker-sync"/>
   <int value="-455203267" label="use_new_features_summary"/>
+  <int value="-449465495" label="disable-browser-task-scheduler"/>
   <int value="-430360431" label="disable-password-generation"/>
   <int value="-418868128" label="enable-experimental-web-platform-features"/>
   <int value="-396994784" label="enable-vr-shell"/>
@@ -83277,6 +83278,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="-158197254" label="enable-credential-manager-api"/>
   <int value="-147283486" label="enable-network-portal-notification"/>
   <int value="-146552997" label="enable-affiliation-based-matching"/>
+  <int value="-122492389" label="enable-browser-task-scheduler"/>
   <int value="-102537270" label="extension-content-verification"/>
   <int value="-99781021" label="disable-roboto-font-ui"/>
   <int value="-88822940" label="ssl-version-min"/>