Avoid parsing css text if there are identical inline style blocks.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 806e65d0a85943f990681650ae22c5ea79f8fbdb..7b5899c9c3f88e49d40ce1084d132498f6171adb 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -625,6 +625,7 @@ void Document::setCompatibilityMode(CompatibilityMode mode)
     selectorQueryCache().invalidate();
     if (inQuirksMode() != wasInQuirksMode) {
         // All injected stylesheets have to reparse using the different mode.
+        StyleEngine::clearSheetCache();

[esprehn, 2014/01/09 10:05:32]

You still can't do this, loading any quirks mode document would blow away the
cache for all the non-quirks ones. I'd suggest either having separate caches for
quirks vs non quirks or making the sharing standards mode only for now. I'd
start with standards mode only for now.

[tasak, 2014/01/09 11:59:05]

I see. I agree that it is much better to split cache.
Done.

         m_styleEngine->invalidateInjectedStyleSheetCache();
     }
 }