Implement convertToBlob() in OffscreenCanvas

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
index 075df5f754dae124dc6a7bb2b6fc6dac393021cc..a87e3b4066b0efc8dae2576acb0fb7d37dae068c 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -745,10 +745,9 @@ void HTMLCanvasElement::toBlob(BlobCallback* callback,
 
   CanvasAsyncBlobCreator* asyncCreator = CanvasAsyncBlobCreator::create(
       imageData->data(), encodingMimeType, imageData->size(), callback,
-      startTime, document());
+      startTime, &document(), nullptr);
 
-  bool useIdlePeriodScheduling = (encodingMimeType != "image/webp");
-  asyncCreator->scheduleAsyncBlobCreation(useIdlePeriodScheduling, quality);
+  asyncCreator->scheduleAsyncBlobCreation(quality);
 }
 
 void HTMLCanvasElement::addListener(CanvasDrawListener* listener) {