Mass-migrate users of base::ThreadPool() as a trait to base::ThreadPool:: API [blink]

Split blink/ from https://chromium-review.googlesource.com/c/chromium/src/+/2026350
as it had trouble landing in one go.

Added thread_pool.h to third_party/blink/renderer/DEPS

The following script was used to generate this CL (run on every C++
file in the codebase; processing .h before matching .cc/.mm):
https://bugs.chromium.org/p/chromium/issues/detail?id=1026641#c22
(intentionally ignores cleaning post_task.h for now).

TBR=haraken@chromium.org

Bug: 1026641
Change-Id: Ief6f3e47f9c31db794dcb7a791735de51c79a43f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2075137Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744703}

third_party/blink/renderer/DEPS

@@ -38,6 +38,7 @@ include_rules = [
     "+base/sys_byteorder.h",
     "+base/system/sys_info.h",
     "+base/task/post_task.h",
+    "+base/task/thread_pool.h",
     "+base/template_util.h",
     "+base/test/metrics/histogram_tester.h",
     "+base/test/mock_callback.h",

third_party/blink/renderer/core/fileapi/file_test.cc

@@ -5,6 +5,7 @@
 #include "third_party/blink/renderer/core/fileapi/file.h"
 
 #include "base/task/post_task.h"
+#include "base/task/thread_pool.h"
 #include "mojo/public/cpp/bindings/receiver_set.h"
 #include "mojo/public/cpp/bindings/self_owned_receiver.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -26,7 +27,7 @@ class MockBlob : public FakeBlob {
   static void Create(File* file, base::Time modified_time) {
     mojo::PendingRemote<mojom::blink::Blob> remote;
     PostCrossThreadTask(
-        *base::CreateSingleThreadTaskRunner({base::ThreadPool()}), FROM_HERE,
+        *base::ThreadPool::CreateSingleThreadTaskRunner({}), FROM_HERE,
         CrossThreadBindOnce(
             [](const String& uuid,
                mojo::PendingReceiver<mojom::blink::Blob> receiver,

third_party/blink/renderer/modules/storage/storage_controller_test.cc

@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/run_loop.h"
 #include "base/task/post_task.h"
+#include "base/task/thread_pool.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
 #include "mojo/public/cpp/bindings/remote.h"
@@ -65,7 +66,7 @@ TEST(StorageControllerTest, CacheLimit) {
 
   StorageController::DomStorageConnection connection;
   PostCrossThreadTask(
-      *base::CreateSequencedTaskRunner({base::ThreadPool()}), FROM_HERE,
+      *base::ThreadPool::CreateSequencedTaskRunner({}), FROM_HERE,
       CrossThreadBindOnce(
           [](mojo::PendingReceiver<mojom::blink::DomStorage> receiver) {
             mojo::MakeSelfOwnedReceiver(std::make_unique<MockDomStorage>(),
@@ -116,7 +117,7 @@ TEST(StorageControllerTest, CacheLimitSessionStorage) {
   Persistent<FakeAreaSource> source_area =
       MakeGarbageCollected<FakeAreaSource>(kPageUrl);
 
-  auto task_runner = base::CreateSequencedTaskRunner({base::ThreadPool()});
+  auto task_runner = base::ThreadPool::CreateSequencedTaskRunner({});
 
   auto mock_dom_storage = std::make_unique<MockDomStorage>();
   MockDomStorage* dom_storage_ptr = mock_dom_storage.get();

third_party/blink/renderer/modules/webdatabase/web_database_host.cc

@@ -9,6 +9,7 @@
 #include "base/single_thread_task_runner.h"
 #include "base/task/post_task.h"
 #include "base/task/task_traits.h"
+#include "base/task/thread_pool.h"
 #include "third_party/blink/public/common/thread_safe_browser_interface_broker_proxy.h"
 #include "third_party/blink/public/mojom/webdatabase/web_database.mojom-blink.h"
 #include "third_party/blink/public/platform/platform.h"
@@ -38,9 +39,8 @@ mojom::blink::WebDatabaseHost& WebDatabaseHost::GetWebDatabaseHost() {
   if (!shared_remote_) {
     DCHECK(pending_remote_);
     shared_remote_ = mojo::SharedRemote<mojom::blink::WebDatabaseHost>(
-        std::move(pending_remote_),
-        base::CreateSequencedTaskRunner(
-            {base::ThreadPool(), base::WithBaseSyncPrimitives()}));
+        std::move(pending_remote_), base::ThreadPool::CreateSequencedTaskRunner(
+                                        {base::WithBaseSyncPrimitives()}));
   }
 
   return *shared_remote_;

third_party/blink/renderer/platform/blob/blob_bytes_provider.cc

@@ -6,6 +6,7 @@
 
 #include "base/numerics/safe_conversions.h"
 #include "base/task/post_task.h"
+#include "base/task/thread_pool.h"
 #include "mojo/public/cpp/bindings/self_owned_receiver.h"
 #include "third_party/blink/public/platform/platform.h"
 #include "third_party/blink/renderer/platform/instrumentation/histogram.h"
@@ -117,8 +118,8 @@ constexpr size_t BlobBytesProvider::kMaxConsolidatedItemSizeInBytes;
 // static
 BlobBytesProvider* BlobBytesProvider::CreateAndBind(
     mojo::PendingReceiver<mojom::blink::BytesProvider> receiver) {
-  auto task_runner = base::CreateSequencedTaskRunner(
-      {base::ThreadPool(), base::MayBlock(), base::TaskPriority::USER_VISIBLE});
+  auto task_runner = base::ThreadPool::CreateSequencedTaskRunner(
+      {base::MayBlock(), base::TaskPriority::USER_VISIBLE});
   auto provider = base::WrapUnique(new BlobBytesProvider(task_runner));
   auto* result = provider.get();
   // TODO(mek): Consider binding BytesProvider on the IPC thread instead, only