Not for review - Rebase of crrev.com/62833003

Source/platform/UIWebThreadSupportingGC.cpp

+#include "config.h"
+#include "UIWebThreadSupportingGC.h"
+#include "WebThreadRawPtr.h"
+
+namespace blink {
+
+PassOwnPtr<UIWebThreadSupportingGC> UIWebThreadSupportingGC::create(const char* name)
+{
+    return adoptPtr(new UIWebThreadSupportingGC(name));
+}
+
+UIWebThreadSupportingGC::UIWebThreadSupportingGC(const char* name)
+    // : m_thread(WebThreadRawPtr(blink::Platform::current()->createThread(name)))
+    : m_attachedThreads(0)
+{
+    m_thread = new WebThreadRawPtr(blink::Platform::current()->createThread(name));
+}
+
+UIWebThreadSupportingGC::UIWebThreadSupportingGC(WebThread* t)
+    // : m_thread(WebThreadRawPtr(t))
+    : m_attachedThreads(0)
+{
+    m_thread = new WebThreadRawPtr(t);
+}
+
+void UIWebThreadSupportingGC::attachGC() {
+    if (m_attachedThreads == 0)
+        WebThreadSupportingGC::attachGC();
+
+    m_attachedThreads++;
+}
+
+void UIWebThreadSupportingGC::detachGC() {
+    m_attachedThreads--;
+
+    if (m_attachedThreads == 0)
+        WebThreadSupportingGC::detachGC();
+}
+
+UIWebThreadSupportingGC::ThreadMap* UIWebThreadSupportingGC::m_threadMap;
+
+UIWebThreadSupportingGC* UIWebThreadSupportingGC::get(WebThread* t) {
+    if (!m_threadMap)
+        m_threadMap = new ThreadMap(); // TODO should be ownptr
+
+    ThreadMap::const_iterator iter = m_threadMap->find(t);
+    if (iter != m_threadMap->end()) {
+        return iter->value;
+    }
+
+    UIWebThreadSupportingGC* uiWebThread = new UIWebThreadSupportingGC(t);
+    m_threadMap->add(t, uiWebThread);
+
+    return uiWebThread;
+}
+
+}