Block the HTML parser on external stylesheets

third_party/WebKit/Source/core/dom/Document.cpp

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 93a13ab219b2a1740691546634dd51c213453042..6920e1c3d6b5703a4994a2cf3cb113317872db9f 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -2095,6 +2095,11 @@ void Document::setIsViewSource(bool isViewSource)
     didUpdateSecurityOrigin();
 }
 
+bool Document::isRenderingReady() const 
+{
+    return haveImportsLoaded() && (RuntimeEnabledFeatures::htmlParserBlocksOnCSSEnabled() || haveStylesheetsLoaded());

[esprehn, 2016/03/07 21:35:50]

I don't think you want to do this, isRenderingReady() prevents painting, but the
parser being blocked on sheet shouldn't block painting. You want the content to
paint.

[Pat Meenan, 2016/03/07 21:49:53]

Right.  The change basically removes the check of stylesheets having been loaded
from the "isRenderingReady" check.  When the new code is enabled, the pending
stylesheets won't be checked for "isRenderingReady".

Given that I need to look at blocking on imports as well this will change a bit
though and neither will block rendering when the code is enabled.

+}
+
 bool Document::dirtyElementsForLayerUpdate()
 {
     if (m_layerUpdateSVGFilterElements.isEmpty())