Don't delay submit in onsubmit event handler

Source/core/html/HTMLFormElement.cpp

Index: Source/core/html/HTMLFormElement.cpp
diff --git a/Source/core/html/HTMLFormElement.cpp b/Source/core/html/HTMLFormElement.cpp
index 7e5a7859d87924d3238f3ac9ad3b22a6f35a131a..48d208acc3d5b3b822b7f9181d02d9973341aac4 100644
--- a/Source/core/html/HTMLFormElement.cpp
+++ b/Source/core/html/HTMLFormElement.cpp
@@ -303,13 +303,21 @@ bool HTMLFormElement::prepareForSubmission(Event* event)
     RefPtr<FormState> formState = FormState::create(this, controlNamesAndValues, &document(), NotSubmittedByJavaScript);
     frame->loader().client()->dispatchWillSendSubmitEvent(formState.release());
 
-    if (dispatchEvent(Event::createCancelableBubble(EventTypeNames::submit)))
-        m_shouldSubmit = true;
-
+    // Set flag before submission as dispatchEvent could trigger another event
     m_isSubmittingOrPreparingForSubmission = false;
 
-    if (m_shouldSubmit)
+    // http://www.whatwg.org/specs/web-apps/current-work/#concept-form-submit
+    // Submit Event can be cancelled i.e. returned false or can explicitly declare default prevented
+    // http://www.w3.org/TR/DOM-Level-3-Events/#event-flow-default-cancel.
+    // Returning false is also considered as default prevented.
+    if (!dispatchEvent(Event::createCancelableBubble(EventTypeNames::submit))
+        || event->defaultPrevented()) {

[keishi, 2014/02/25 15:00:57]

I think prepareForSubmission is always called from defaultEventHandler() so
event->defaultPrevented() should always be false. Maybe this should be an
ASSERT.

+        return m_shouldSubmit; // i.e. do not proceed
+    }
+    if (!m_shouldSubmit) {
+        m_shouldSubmit = true;
         submit(event, true, true, NotSubmittedByJavaScript);
+    }
 
     return m_shouldSubmit;
 }
@@ -358,14 +366,9 @@ void HTMLFormElement::submit(Event* event, bool activateSubmitButton, bool proce
 {
     FrameView* view = document().view();
     Frame* frame = document().frame();
-    if (!view || !frame || !frame->page())
+    if (!view || !frame || !frame->page() || m_isSubmittingOrPreparingForSubmission)
         return;
 
-    if (m_isSubmittingOrPreparingForSubmission) {
-        m_shouldSubmit = true;
-        return;
-    }
-
     m_isSubmittingOrPreparingForSubmission = true;
     m_wasUserSubmitted = processingUserGesture;