Oilpan: promptly dispose style resolvers upon clearing.

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

Index: third_party/WebKit/Source/core/dom/StyleEngine.cpp
diff --git a/third_party/WebKit/Source/core/dom/StyleEngine.cpp b/third_party/WebKit/Source/core/dom/StyleEngine.cpp
index 911f80a8e9fae0bf945bcae6ae0992cfaf416e35..0588074be6a2cf90f442f116cdf653d485fd46d0 100644
--- a/third_party/WebKit/Source/core/dom/StyleEngine.cpp
+++ b/third_party/WebKit/Source/core/dom/StyleEngine.cpp
@@ -427,6 +427,15 @@ void StyleEngine::clearResolver()
 
     if (m_resolver) {
         TRACE_EVENT1("blink", "StyleEngine::clearResolver", "frame", document().frame());
+#if ENABLE(OILPAN)
+        // The StyleResolver is a heavy object having a number of collection objects
+        // attached. Attempt to promptly recycle their backing storage objects which
+        // are on the Oilpan collection heaps, so as to increase the chance of
+        // heap storage reuse without having to involve the Oilpan GC. Helpful for
+        // workloads that stresses (re)creation of StyleResolvers and/or have high
+        // allocation rates.
+        m_resolver->dispose();
+#endif
         m_resolver.clear();
     }
 }