XHR: separate delayed progress event flushing from dispatching of new.

Source/core/xml/XMLHttpRequestProgressEventThrottle.cpp

Index: Source/core/xml/XMLHttpRequestProgressEventThrottle.cpp
diff --git a/Source/core/xml/XMLHttpRequestProgressEventThrottle.cpp b/Source/core/xml/XMLHttpRequestProgressEventThrottle.cpp
index 212bf9d835f6ac34a12bb0af191d57b750f6b36f..05e8179418323b53da9206d25330766e156f858d 100644
--- a/Source/core/xml/XMLHttpRequestProgressEventThrottle.cpp
+++ b/Source/core/xml/XMLHttpRequestProgressEventThrottle.cpp
@@ -77,8 +77,10 @@ void XMLHttpRequestProgressEventThrottle::dispatchProgressEvent(bool lengthCompu
 
 void XMLHttpRequestProgressEventThrottle::dispatchReadyStateChangeEvent(PassRefPtr<Event> event, ProgressEventAction progressEventAction)
 {
-    if (progressEventAction == FlushProgressEvent)
-        flushProgressEvent();
+    if (progressEventAction == FlushProgressEvent || progressEventAction == FlushDeferredProgressEvent) {
+        if (!flushDeferredProgressEvent() && progressEventAction == FlushProgressEvent)
+            deliverProgressEvent();
+    }
 
     dispatchEvent(event);
 }
@@ -104,15 +106,19 @@ void XMLHttpRequestProgressEventThrottle::dispatchEventAndLoadEnd(PassRefPtr<Eve
     dispatchEvent(XMLHttpRequestProgressEvent::create(EventTypeNames::loadend));
 }
 
-void XMLHttpRequestProgressEventThrottle::flushProgressEvent()
+bool XMLHttpRequestProgressEventThrottle::flushDeferredProgressEvent()
 {
     if (m_deferEvents && m_deferredProgressEvent) {
         // Move the progress event to the queue, to get it in the right order on resume.
         m_deferredEvents.append(m_deferredProgressEvent);
         m_deferredProgressEvent = 0;
-        return;
+        return true;
     }
+    return false;
+}
 
+void XMLHttpRequestProgressEventThrottle::deliverProgressEvent()
+{
     if (!hasEventToDispatch())
         return;