[scheduler] Remove BrowserTaskType::kNavigation

We do not and should not use kNavigation task type.
Remove it to eliminate the risk of the potential misuse.

R=nasko@chromium.org,gab@chromium.org

Change-Id: I900a7115224a6ca431167a3698e11ea6bd1ed180
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2063021Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Auto-Submit: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747534}

content/browser/scheduler/browser_task_executor.cc

@@ -129,11 +129,10 @@ QueueType BaseBrowserTaskExecutor::GetQueueType(
         // Note we currently ignore the priority for bootstrap tasks.
         return QueueType::kBootstrap;
 
-      case BrowserTaskType::kNavigation:
       case BrowserTaskType::kPreconnect:
         // Note we currently ignore the priority for navigation and
         // preconnection tasks.
-        return QueueType::kNavigationAndPreconnection;
+        return QueueType::kPreconnection;
 
       case BrowserTaskType::kDefault:
         // Defer to traits.priority() below.

content/browser/scheduler/browser_task_executor_unittest.cc

@@ -149,10 +149,8 @@ TEST_F(BrowserTaskTraitsMappingTest, BrowserTaskTraitsMapToProperPriorities) {
             QueueType::kBootstrap);
   EXPECT_EQ(BrowserTaskExecutor::GetQueueType({BrowserTaskType::kDefault}),
             QueueType::kUserBlocking);
-  EXPECT_EQ(BrowserTaskExecutor::GetQueueType({BrowserTaskType::kNavigation}),
-            QueueType::kNavigationAndPreconnection);
   EXPECT_EQ(BrowserTaskExecutor::GetQueueType({BrowserTaskType::kPreconnect}),
-            QueueType::kNavigationAndPreconnection);
+            QueueType::kPreconnection);
 
   EXPECT_EQ(BrowserTaskExecutor::GetQueueType({}), QueueType::kUserBlocking);
 }

content/browser/scheduler/browser_task_queues.cc

@@ -55,7 +55,7 @@ const char* GetUITaskQueueName(BrowserTaskQueues::QueueType queue_type) {
       return "ui_best_effort_tq";
     case BrowserTaskQueues::QueueType::kBootstrap:
       return "ui_bootstrap_tq";
-    case BrowserTaskQueues::QueueType::kNavigationAndPreconnection:
+    case BrowserTaskQueues::QueueType::kPreconnection:
       return "ui_navigation_and_preconnection_tq";
     case BrowserTaskQueues::QueueType::kDefault:
       return "ui_default_tq";
@@ -72,7 +72,7 @@ const char* GetIOTaskQueueName(BrowserTaskQueues::QueueType queue_type) {
       return "io_best_effort_tq";
     case BrowserTaskQueues::QueueType::kBootstrap:
       return "io_bootstrap_tq";
-    case BrowserTaskQueues::QueueType::kNavigationAndPreconnection:
+    case BrowserTaskQueues::QueueType::kPreconnection:
       return "io_navigation_and_preconnection_tq";
     case BrowserTaskQueues::QueueType::kDefault:
       return "io_default_tq";
@@ -223,7 +223,7 @@ void BrowserTaskQueues::PostFeatureListInitializationSetup() {
 
     // Navigation and preconnection tasks are also important during startup so
     // prioritize them too.
-    GetBrowserTaskQueue(QueueType::kNavigationAndPreconnection)
+    GetBrowserTaskQueue(QueueType::kPreconnection)
         ->SetQueuePriority(QueuePriority::kHighPriority);
   }
 }

content/browser/scheduler/browser_task_queues.h

@@ -50,8 +50,8 @@ class CONTENT_EXPORT BrowserTaskQueues {
     // For tasks on the critical path up to issuing the initial navigation.
     kBootstrap,
 
-    // For navigation and preconnection related tasks.
-    kNavigationAndPreconnection,
+    // For preconnection-related tasks.
+    kPreconnection,
 
     // base::TaskPriority::kUserBlocking maps to this task queue. It's for tasks
     // that affect the UI immediately after a user interaction. Has the same

content/public/android/java/src/org/chromium/content_public/browser/BrowserTaskExecutor.java

@@ -95,7 +95,6 @@ public class BrowserTaskExecutor implements TaskExecutor {
 
         switch (impl.getTaskType()) {
             case BrowserTaskType.BOOTSTRAP:
-            case BrowserTaskType.NAVIGATION:
                 return true;
 
             default:

content/public/browser/browser_task_traits.h

@@ -36,9 +36,6 @@ enum class BrowserTaskType {
   // Critical startup tasks.
   kBootstrap,
 
-  // Navigation related tasks.
-  kNavigation,
-
   // A subset of network tasks related to preconnection.
   kPreconnect,
 

content/public/browser/browser_task_traits_unittest.nc

@@ -15,8 +15,7 @@ namespace content {
 constexpr base::TaskTraits traits = {BrowserThread::UI,
                                      BrowserThread::IO};
 #elif defined(NCTEST_BROWSER_TASK_TRAITS_MULTIPLE_TASK_TYPES)  // [r"The traits bag contains multiple traits of the same type."]
-constexpr base::TaskTraits traits = {BrowserTaskType::kNavigation,
-                                     BrowserTaskType::kBootstrap};
+constexpr base::TaskTraits traits = {BrowserTaskType::kBootstrap, BrowserTaskType::kPreconnect};
 #endif