Drop unecessary use of CrossThreadPersistent by CanvasAsyncBlobCreator.

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

Index: third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.cpp
diff --git a/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.cpp b/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.cpp
index 01136649524082b8b79b83dda662a2a4852c957e..007947c366e67c3bd4d36e2f8cf99ac28c9aa18f 100644
--- a/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.cpp
+++ b/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreator.cpp
@@ -256,20 +256,12 @@ void CanvasAsyncBlobCreator::createBlobAndInvokeCallback()
     ASSERT(isMainThread());
     Blob* resultBlob = Blob::create(m_encodedImage->data(), m_encodedImage->size(), convertMimeTypeEnumToString(m_mimeType));
     Platform::current()->mainThread()->getWebTaskRunner()->postTask(BLINK_FROM_HERE, bind(&BlobCallback::handleEvent, m_callback, resultBlob));
-    // Since toBlob is done, timeout events are no longer needed. So we clear

[sof, 2016/06/13 06:15:26]

This CL may have introduced some leaks


https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Leak/b...

Taking a look (not clearing the callback the reason..?)

-    // non-GC members to allow teardown of CanvasAsyncBlobCreator.
-    m_data.clear();
-    m_callback.clear();
 }
 
 void CanvasAsyncBlobCreator::createNullAndInvokeCallback()
 {
     ASSERT(isMainThread());
     Platform::current()->mainThread()->getWebTaskRunner()->postTask(BLINK_FROM_HERE, bind(&BlobCallback::handleEvent, m_callback, nullptr));
-    // Since toBlob is done (failed), timeout events are no longer needed. So we
-    // clear non-GC members to allow teardown of CanvasAsyncBlobCreator.
-    m_data.clear();
-    m_callback.clear();
 }
 
 void CanvasAsyncBlobCreator::encodeImageOnEncoderThread(double quality)