Reduce use of ExecutionContextTask in core/

third_party/WebKit/Source/core/clipboard/DataTransferItem.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/clipboard/DataTransferItem.h"
 
 #include "bindings/core/v8/V8Binding.h"
 #include "core/clipboard/DataObjectItem.h"
 #include "core/clipboard/DataTransfer.h"
-#include "core/dom/ExecutionContext.h"
-#include "core/dom/ExecutionContextTask.h"
 #include "core/dom/StringCallback.h"
 #include "core/dom/TaskRunnerHelper.h"
+#include "core/inspector/InspectorInstrumentation.h"
 #include "public/platform/WebTraceLocation.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 DataTransferItem* DataTransferItem::create(DataTransfer* dataTransfer,
                                            DataObjectItem* item) {
   return new DataTransferItem(dataTransfer, item);
 }
@@ skipping 12 matching lines @@
   ASSERT_NOT_REACHED();
   return String();
 }
 
 String DataTransferItem::type() const {
   if (!m_dataTransfer->canReadTypes())
     return String();
   return m_item->type();
 }
 
+static void runGetAsStringTask(ExecutionContext* context,
+                               StringCallback* callback,
+                               const String& data) {
+  InspectorInstrumentation::AsyncTask(context, callback);
+  callback->handleEvent(data);
+}
+
 void DataTransferItem::getAsString(ScriptState* scriptState,
                                    StringCallback* callback) const {
   if (!m_dataTransfer->canReadData())
     return;
   if (!callback || m_item->kind() != DataObjectItem::StringKind)
     return;
 
-  scriptState->getExecutionContext()->postTask(
-      TaskType::UserInteraction, BLINK_FROM_HERE,
-      createSameThreadTask(&StringCallback::handleEvent,
-                           wrapPersistent(callback), m_item->getAsString()),
-      "DataTransferItem.getAsString");
+  ExecutionContext* context = scriptState->getExecutionContext();
+  InspectorInstrumentation::asyncTaskScheduled(
+      context, "DataTransferItem.getAsString", callback);
+  TaskRunnerHelper::get(TaskType::UserInteraction, context)
+      ->postTask(BLINK_FROM_HERE,
+                 WTF::bind(&runGetAsStringTask, wrapPersistent(context),

[tzik, 2017/02/09 12:15:34]

Could you replace wrapPersistent(context) here with wrapWeakPersistent(context),
and add a null check to runGetAsStringTask?
On the previous code, ExecutionContext::postTask cancels the posted task when
ExecutionContext is destroyed, and the posted task doesn't retain the strong
reference to ExecutionContext. I think we should keep previous behavior now.

[yuryu, 2017/02/09 12:56:43]

Done.

+                           wrapPersistent(callback), m_item->getAsString()));
 }
 
 File* DataTransferItem::getAsFile() const {
   if (!m_dataTransfer->canReadData())
     return nullptr;
 
   return m_item->getAsFile();
 }
 
 DataTransferItem::DataTransferItem(DataTransfer* dataTransfer,
                                    DataObjectItem* item)
     : m_dataTransfer(dataTransfer), m_item(item) {}
 
 DEFINE_TRACE(DataTransferItem) {
   visitor->trace(m_dataTransfer);
   visitor->trace(m_item);
 }
 
 }  // namespace blink