<rdar://problem/6803905> Lots of ASSERTs firing when trying to clear history

        Reviewed by Steve Falkenburg.

        * WebHistory.cpp:
        (WebHistory::data): Return null if there are no history items.



git-svn-id: svn://svn.chromium.org/blink/trunk@42630 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/WebKit/win/ChangeLog

+2009-04-17  Ada Chan  <adachan@apple.com>
+
+        <rdar://problem/6803905> Lots of ASSERTs firing when trying to clear history
+
+        Reviewed by Steve Falkenburg.
+
+        * WebHistory.cpp:
+        (WebHistory::data): Return null if there are no history items.
+
 2009-04-17  Ada Chan  <adachan@apple.com>
 
         - Fix a leak in WebHistoryItem::children() by adopting the created instance of WebHistoryItem.

third_party/WebKit/WebKit/win/WebHistory.cpp

@@ -565,7 +565,11 @@ HRESULT WebHistory::data(IStream** stream)
 
     *stream = 0;
 
-    COMPtr<MemoryStream> result(AdoptCOM, MemoryStream::createInstance(SharedBuffer::wrapCFData(data().get())));
+    RetainPtr<CFDataRef> historyData = data();
+    if (!historyData)
+        return S_OK;
+
+    COMPtr<MemoryStream> result(AdoptCOM, MemoryStream::createInstance(SharedBuffer::wrapCFData(historyData.get())));
     return result.copyRefTo(stream);
 }
 
@@ -948,6 +952,9 @@ void WebHistory::addVisitedLinksToPageGroup(PageGroup& group)
 
 RetainPtr<CFDataRef> WebHistory::data() const
 {
+    if (!CFArrayGetCount(m_entriesByDate.get()))
+        return 0;
+
     WebHistoryWriter writer(m_entriesByDate.get());
     writer.writePropertyList();
     return writer.releaseData();