Remove Document::execute_scripts_waiting_for_resources_task_handle_

The task handle is never cancelled, so it can be replaced w/ a simple PostTask.
The task lifetime is managed by weakPersistent anyways.

Bug: None
Change-Id: I191c9cad4982c42ba5d0177d1464d32b31bc2354
Reviewed-on: https://chromium-review.googlesource.com/571110Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kouhei Ueno <kouhei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486726}

third_party/WebKit/Source/core/dom/Document.cpp

@@ -3700,12 +3700,10 @@ void Document::DidRemoveAllPendingBodyStylesheets() {
 void Document::DidLoadAllScriptBlockingResources() {
   // Use wrapWeakPersistent because the task should not keep this Document alive
   // just for executing scripts.
-  execute_scripts_waiting_for_resources_task_handle_ =
-      TaskRunnerHelper::Get(TaskType::kNetworking, this)
-          ->PostCancellableTask(
-              BLINK_FROM_HERE,
-              WTF::Bind(&Document::ExecuteScriptsWaitingForResources,
-                        WrapWeakPersistent(this)));
+  TaskRunnerHelper::Get(TaskType::kNetworking, this)
+      ->PostTask(BLINK_FROM_HERE,
+                 WTF::Bind(&Document::ExecuteScriptsWaitingForResources,
+                           WrapWeakPersistent(this)));
 
   if (IsHTMLDocument() && body()) {
     // For HTML if we have no more stylesheets to load and we're past the body

third_party/WebKit/Source/core/dom/Document.h

@@ -1497,8 +1497,6 @@ class CORE_EXPORT Document : public ContainerNode,
   // This is cheaper than making setCompatibilityMode virtual.
   bool compatibility_mode_locked_;
 
-  TaskHandle execute_scripts_waiting_for_resources_task_handle_;
-
   bool has_autofocused_;
   TaskRunnerTimer<Document> clear_focused_element_timer_;
   Member<Element> autofocus_element_;