XMLHttpRequest: return null upon failing responseArrayBuffer allocation.

third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp

Index: third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
diff --git a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
index c74d9e94739cd731464822eaaff8b2fe52b1bfc5..141603d573116da0d95b87eab645a61c3e758aab 100644
--- a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
+++ b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
@@ -388,11 +388,16 @@ DOMArrayBuffer* XMLHttpRequest::responseArrayBuffer() {
 
   if (!m_responseArrayBuffer) {
     if (m_binaryResponseBuilder && m_binaryResponseBuilder->size()) {
-      DOMArrayBuffer* buffer = DOMArrayBuffer::createUninitialized(
+      DOMArrayBuffer* buffer = DOMArrayBuffer::createUninitializedOrNull(
           m_binaryResponseBuilder->size(), 1);
-      m_binaryResponseBuilder->getAsBytes(
-          buffer->data(), static_cast<size_t>(buffer->byteLength()));
-      m_responseArrayBuffer = buffer;
+      if (buffer) {
+        m_binaryResponseBuilder->getAsBytes(
+            buffer->data(), static_cast<size_t>(buffer->byteLength()));
+        m_responseArrayBuffer = buffer;
+      }
+      // https://xhr.spec.whatwg.org/#arraybuffer-response allows clearing
+      // of the 'received bytes' payload when the response buffer allocation
+      // fails.
       m_binaryResponseBuilder.clear();
     } else {
       m_responseArrayBuffer = DOMArrayBuffer::create(nullptr, 0);

[yhirano, 2017/03/06 09:19:53]

This getter returns null for the first time, and will return an empty
DOMArrayBuffer from the second time, right?

[sof, 2017/03/06 09:29:16]

Hmm, yes. It implements the spec by doing so, I'd say.