Handle OffscreenCanvas.convertToBlob exceptions: EncodingError & InvalidStateError

third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.cpp

 // Copyright 2015 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 "core/html/canvas/CanvasAsyncBlobCreator.h"
 
+#include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/fileapi/Blob.h"
 #include "platform/CrossThreadFunctional.h"
 #include "platform/Histogram.h"
 #include "platform/WebTaskRunner.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/image-encoders/JPEGImageEncoder.h"
 #include "platform/image-encoders/PNGImageEncoder.h"
 #include "platform/threading/BackgroundTaskRunner.h"
@@ skipping 454 matching lines @@
 void CanvasAsyncBlobCreator::createNullAndReturnResult() {
   recordIdleTaskStatusHistogram(m_idleTaskStatus);
   if (m_functionType == HTMLCanvasToBlobCallback) {
     DCHECK(isMainThread());
     recordIdleTaskStatusHistogram(m_idleTaskStatus);
     TaskRunnerHelper::get(TaskType::CanvasBlobSerialization, m_document)
         ->postTask(BLINK_FROM_HERE,
                    WTF::bind(&BlobCallback::handleEvent,
                              wrapPersistent(m_callback.get()), nullptr));
   } else {
-    Blob* blob = nullptr;
-    m_scriptPromiseResolver->reject(blob);
+    m_scriptPromiseResolver->reject(DOMException::create(
+        EncodingError, "Encoding of the source image has failed."));
   }
   // Avoid unwanted retention, see dispose().
   dispose();
 }
 
 void CanvasAsyncBlobCreator::encodeImageOnEncoderThread(double quality) {
   DCHECK(!isMainThread());
   DCHECK(m_mimeType == MimeTypeWebp);
 
   if (!ImageDataBuffer(m_size, m_data->data())
            .encodeImage("image/webp", quality, m_encodedImage.get())) {
     m_parentFrameTaskRunner->get(TaskType::CanvasBlobSerialization)
-        ->postTask(BLINK_FROM_HERE,
-                   crossThreadBind(&BlobCallback::handleEvent,
-                                   wrapCrossThreadPersistent(m_callback.get()),
-                                   nullptr));
+        ->postTask(
+            BLINK_FROM_HERE,
+            crossThreadBind(&CanvasAsyncBlobCreator::createNullAndReturnResult,
+                            wrapCrossThreadPersistent(this)));
     return;
   }
 
   m_parentFrameTaskRunner->get(TaskType::CanvasBlobSerialization)
       ->postTask(
           BLINK_FROM_HERE,
           crossThreadBind(&CanvasAsyncBlobCreator::createBlobAndReturnResult,
                           wrapCrossThreadPersistent(this)));
 }
 
@@ skipping 106 matching lines @@
 
 DEFINE_TRACE(CanvasAsyncBlobCreator) {
   visitor->trace(m_document);
   visitor->trace(m_data);
   visitor->trace(m_callback);
   visitor->trace(m_parentFrameTaskRunner);
   visitor->trace(m_scriptPromiseResolver);
 }
 
 }  // namespace blink