Webfont CORS-enabled fetching with fallback

Source/core/css/CSSFontFaceSrcValue.cpp

Index: Source/core/css/CSSFontFaceSrcValue.cpp
diff --git a/Source/core/css/CSSFontFaceSrcValue.cpp b/Source/core/css/CSSFontFaceSrcValue.cpp
index 5ccf7547707efc0f79d2e69841d9ace072da92cb..f20a3428589a60e2bbc5004bef13c3d34c167c67 100644
--- a/Source/core/css/CSSFontFaceSrcValue.cpp
+++ b/Source/core/css/CSSFontFaceSrcValue.cpp
@@ -39,6 +39,30 @@
 
 namespace WebCore {
 
+CSSFontFaceSrcValue::FontResourceInvalidator::FontResourceInvalidator(CSSFontFaceSrcValue& srcValue)
+    : m_srcValue(srcValue)
+    , m_resource(srcValue.m_fetched)
+{
+    m_resource->addClient(this);

[Kunihiko Sakamoto, 2014/04/10 05:49:24]

Resource cancels in-flight request when all clients are removed.
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

This change makes FontResource always have one client (invalidator), so
cancellation won't work for fonts.

Instead of using the invalidator, maybe we can just clear m_fetched in the
beginning of CSSFontFaceSrcValue::fetch() if m_corsFailed is true?

[bashi, 2014/04/10 07:05:51]

Great suggestion! Done.

+}
+
+CSSFontFaceSrcValue::FontResourceInvalidator::~FontResourceInvalidator()
+{
+    m_resource->removeClient(this);
+}
+
+void CSSFontFaceSrcValue::FontResourceInvalidator::fontLoaded(FontResource*)
+{
+    m_srcValue.m_invalidator.clear();
+}
+
+void CSSFontFaceSrcValue::FontResourceInvalidator::corsFailed(FontResource*)
+{
+    m_srcValue.m_fetched.clear();
+    m_srcValue.m_corsEnabled = NotCORSEnabled;
+    m_srcValue.m_invalidator.clear();
+}
+
 #if ENABLE(SVG_FONTS)
 bool CSSFontFaceSrcValue::isSVGFontFaceSrc() const
 {
@@ -88,11 +112,23 @@ bool CSSFontFaceSrcValue::hasFailedOrCanceledSubresources() const
     return m_fetched->loadFailedOrCanceled();
 }
 
+bool CSSFontFaceSrcValue::shouldSetCrossOriginAccessControl(const KURL& resource, SecurityOrigin* securityOrigin)
+{
+    if (m_corsEnabled == NotCORSEnabled || resource.isLocalFile() || resource.protocolIsData())
+        return false;
+    return !securityOrigin->canRequest(resource);
+}
+
 FontResource* CSSFontFaceSrcValue::fetch(Document* document)
 {
     if (!m_fetched) {
         FetchRequest request(ResourceRequest(document->completeURL(m_resource)), FetchInitiatorTypeNames::css);
+        SecurityOrigin* securityOrigin = document->securityOrigin();
+        if (shouldSetCrossOriginAccessControl(request.url(), securityOrigin)) {
+            request.setCrossOriginAccessControl(securityOrigin, DoNotAllowStoredCredentials);
+        }
         m_fetched = document->fetcher()->fetchFont(request);
+        m_invalidator = adoptPtr(new FontResourceInvalidator(*this));
     }
     return m_fetched.get();
 }