Use timer task runner for V8PerIsolate tasks

pdf/pdfium/pdfium_engine.cc

 // Copyright (c) 2012 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 "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
 #include <memory>
 #include <set>
 
 #include "base/auto_reset.h"
 #include "base/i18n/encoding_detection.h"
 #include "base/i18n/icu_string_conversions.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "gin/array_buffer.h"
 #include "gin/public/gin_embedders.h"
 #include "gin/public/isolate_holder.h"
 #include "pdf/draw_utils.h"
 #include "pdf/pdfium/pdfium_api_string_buffer_adapter.h"
 #include "pdf/pdfium/pdfium_mem_buffer_file_read.h"
 #include "pdf/pdfium/pdfium_mem_buffer_file_write.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_input_event.h"
 #include "ppapi/c/ppb_core.h"
@@ skipping 561 matching lines @@
       FPDF_GetMetaText(doc, key.c_str(), string_adapter.GetData(), size));
   return base::UTF16ToUTF8(value);
 }
 
 gin::IsolateHolder* g_isolate_holder = nullptr;
 
 void SetUpV8() {
   gin::IsolateHolder::Initialize(gin::IsolateHolder::kNonStrictMode,
                                  gin::IsolateHolder::kStableV8Extras,
                                  gin::ArrayBufferAllocator::SharedInstance());
-  g_isolate_holder =
-      new gin::IsolateHolder(gin::IsolateHolder::kSingleThread);
+  g_isolate_holder = new gin::IsolateHolder(base::ThreadTaskRunnerHandle::Get(),
+                                            gin::IsolateHolder::kSingleThread);
   g_isolate_holder->isolate()->Enter();
 }
 
 void TearDownV8() {
   g_isolate_holder->isolate()->Exit();
   delete g_isolate_holder;
   g_isolate_holder = nullptr;
 }
 
 }  // namespace
@@ skipping 3517 matching lines @@
   FPDF_DOCUMENT doc =
       FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, nullptr);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf