Initialize TaskScheduler in renderers.

content/public/renderer/content_renderer_client.cc

Index: content/public/renderer/content_renderer_client.cc
diff --git a/content/public/renderer/content_renderer_client.cc b/content/public/renderer/content_renderer_client.cc
index 642521f5819662f50c28f83e12418c2ca6632a26..b276888086864ca5309db4720d1542013059af59 100644
--- a/content/public/renderer/content_renderer_client.cc
+++ b/content/public/renderer/content_renderer_client.cc
@@ -4,6 +4,12 @@
 
 #include "content/public/renderer/content_renderer_client.h"
 
+#include "base/bind.h"
+#include "base/task_scheduler/initialization_util.h"
+#include "base/task_scheduler/scheduler_worker_pool_params.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
 #include "cc/blimp/remote_compositor_bridge.h"
 #include "content/public/renderer/media_stream_renderer_factory.h"
 #include "media/base/renderer_factory.h"
@@ -12,6 +18,24 @@
 
 namespace content {
 
+namespace {
+
+enum WorkerPoolType : size_t {
+  BACKGROUND_WORKER_POOL = 0,
+  FOREGROUND_WORKER_POOL,

[gab, 2016/11/18 18:31:59]

Not used anywhere but in GetTaskSchedulerWorkerPoolIndexForTraits()?

I think you had DCHECK_EQ comparing size before insertion with these before, I
guess that'd be one way to highlight where they come from?

Or we could just use 0/1 directly IMO if everything is inlined below and it's
clear.

+  WORKER_POOL_COUNT  // Always last.
+};
+
+size_t GetTaskSchedulerWorkerPoolIndexForTraits(
+    const base::TaskTraits& traits) {
+  DCHECK(!traits.with_file_io());
+  return traits.priority() == base::TaskPriority::BACKGROUND
+             ? BACKGROUND_WORKER_POOL
+             : FOREGROUND_WORKER_POOL;
+}

[gab, 2016/11/18 18:31:59]

I'd prefer for this to be inlined in method's scope.

+
+}  // namespace
+
 SkBitmap* ContentRendererClient::GetSadPluginBitmap() {
   return nullptr;
 }
@@ -44,6 +68,43 @@ bool ContentRendererClient::ShouldSuppressErrorPage(RenderFrame* render_frame,
   return false;
 }
 
+void ContentRendererClient::GetTaskSchedulerInitializationArguments(
+    std::vector<base::SchedulerWorkerPoolParams>* worker_pool_params_vector,
+    base::Callback<size_t(const base::TaskTraits& traits)>*
+        worker_pool_index_for_traits_callback,
+    bool* redirect_sequenced_worker_pool) {
+  constexpr int kBackgroundThreadsMin = 3;
+  constexpr int kBackgroundThreadsMax = 8;
+  constexpr double kBackgroundThreadsCoresMultiplier = 0.1;
+  constexpr int kBackgroundThreadsOffset = 0;
+  worker_pool_params_vector->emplace_back(
+      "RendererBackground", base::ThreadPriority::NORMAL,
+      base::SchedulerWorkerPoolParams::IORestriction::DISALLOWED,
+      base::SchedulerWorkerPoolParams::StandbyThreadPolicy::LAZY,
+      base::RecommendedMaxNumberOfThreadsInPool(
+          kBackgroundThreadsMin, kBackgroundThreadsMax,
+          kBackgroundThreadsCoresMultiplier, kBackgroundThreadsOffset),
+      base::TimeDelta::FromSeconds(30));
+
+  constexpr int kForegroundThreadsMin = 8;
+  constexpr int kForegroundThreadsMax = 32;
+  constexpr double kForegroundThreadsCoresMultiplier = 0.3;
+  constexpr int kForegroundThreadsOffset = 0;

[gab, 2016/11/18 18:31:59]

These constants are probably too high for the renderers (unlike the browser
there's more than one instance of them).

"8" as a magic number was initially based on 3 BlockingPool + 5 CachePool being
the main consumers in browser land.

Thoughts on what magic numbers make sense for the renderers?

+  worker_pool_params_vector->emplace_back(
+      "RendererForeground", base::ThreadPriority::NORMAL,
+      base::SchedulerWorkerPoolParams::IORestriction::DISALLOWED,
+      base::SchedulerWorkerPoolParams::StandbyThreadPolicy::LAZY,
+      base::RecommendedMaxNumberOfThreadsInPool(
+          kForegroundThreadsMin, kForegroundThreadsMax,
+          kForegroundThreadsCoresMultiplier, kForegroundThreadsOffset),
+      base::TimeDelta::FromSeconds(30));
+
+  *worker_pool_index_for_traits_callback =
+      base::Bind(&GetTaskSchedulerWorkerPoolIndexForTraits);
+
+  *redirect_sequenced_worker_pool = false;
+}
+
 void ContentRendererClient::DeferMediaLoad(
     RenderFrame* render_frame,
     bool has_played_media_before,