Oilpan: move 2D Canvas and WebGL objects to the heap.

Source/core/html/canvas/WebGLContextGroup.cpp

Index: Source/core/html/canvas/WebGLContextGroup.cpp
diff --git a/Source/core/html/canvas/WebGLContextGroup.cpp b/Source/core/html/canvas/WebGLContextGroup.cpp
index e9e3ebe267e639e30864491c04db7236a589b020..1eeb1ad91ddcaffc2b0b757065fd1034423fdb64 100644
--- a/Source/core/html/canvas/WebGLContextGroup.cpp
+++ b/Source/core/html/canvas/WebGLContextGroup.cpp
@@ -31,25 +31,36 @@
 
 namespace WebCore {
 
-PassRefPtr<WebGLContextGroup> WebGLContextGroup::create()
+PassRefPtrWillBeRawPtr<WebGLContextGroup> WebGLContextGroup::create()
 {
-    RefPtr<WebGLContextGroup> contextGroup = adoptRef(new WebGLContextGroup());
+    RefPtrWillBeRawPtr<WebGLContextGroup> contextGroup = adoptRefWillBeNoop(new WebGLContextGroup());
     return contextGroup.release();
 }
 
 WebGLContextGroup::WebGLContextGroup()
+#if ENABLE(OILPAN)
+    : m_savedContext(0)
+#endif
 {
 }
 
+#if !ENABLE(OILPAN)
 WebGLContextGroup::~WebGLContextGroup()
 {
     detachAndRemoveAllObjects();
 }
+#endif
 
 blink::WebGraphicsContext3D* WebGLContextGroup::getAWebGraphicsContext3D()
 {
+#if ENABLE(OILPAN)
+    ASSERT(!m_contexts.isEmpty() || m_savedContext);
+    if (m_savedContext)
+        return m_savedContext;
+#else
     ASSERT(!m_contexts.isEmpty());
-    HashSet<WebGLRenderingContextBase*>::iterator it = m_contexts.begin();
+#endif
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<WebGLRenderingContextBase> >::iterator it = m_contexts.begin();
     return (*it)->webContext();
 }
 
@@ -69,6 +80,13 @@ void WebGLContextGroup::removeContext(WebGLRenderingContextBase* context)
 
 void WebGLContextGroup::removeObject(WebGLSharedObject* object)
 {
+#if ENABLE(OILPAN)
+    // Oilpan: if removal happens during weak callback processing, ignore.
+    // Done so as to prevent re-allocation of the backing store; the table
+    // is cleared afterwards instead.
+    if (m_savedContext)
+        return;
+#endif
     m_groupObjects.remove(object);
 }
 
@@ -80,7 +98,7 @@ void WebGLContextGroup::addObject(WebGLSharedObject* object)
 void WebGLContextGroup::detachAndRemoveAllObjects()
 {
     while (!m_groupObjects.isEmpty()) {
-        HashSet<WebGLSharedObject*>::iterator it = m_groupObjects.begin();
+        WillBeHeapHashSet<RawPtrWillBeWeakMember<WebGLSharedObject> >::iterator it = m_groupObjects.begin();
         (*it)->detachContextGroup();
     }
 }
@@ -91,8 +109,36 @@ void WebGLContextGroup::loseContextGroup(WebGLRenderingContextBase::LostContextM
     // and prevents groupObjects from being properly deleted.
     detachAndRemoveAllObjects();
 
-    for (HashSet<WebGLRenderingContextBase*>::iterator it = m_contexts.begin(); it != m_contexts.end(); ++it)
+    for (WillBeHeapHashSet<RawPtrWillBeWeakMember<WebGLRenderingContextBase> >::iterator it = m_contexts.begin(); it != m_contexts.end(); ++it)
         (*it)->loseContextImpl(mode);
 }
 
+void WebGLContextGroup::clearWeakMembers(Visitor*)
+{
+#if ENABLE(OILPAN)
+    // We must call detachAndRemoveAllObjects when there are no contexts left.
+    // In order to be able to provide the group objects with the WebGraphicsContext3D
+    // object they need on detach, one is saved away during tracing.
+    if (!m_contexts.size() && m_savedContext) {
+        detachAndRemoveAllObjects();
+        m_groupObjects.clear();
+    }
+    m_savedContext = 0;
+#endif
+}
+
+void WebGLContextGroup::trace(Visitor* visitor)
+{
+#if ENABLE(OILPAN)
+    // See clearWeakMembers() comment.
+    if (m_contexts.size() && m_groupObjects.size()) {
+        m_savedContext = getAWebGraphicsContext3D();
+        ASSERT(m_savedContext);
+    }
+#endif
+    visitor->trace(m_contexts);
+    visitor->trace(m_groupObjects);
+    visitor->registerWeakMembers<WebGLContextGroup, &WebGLContextGroup::clearWeakMembers>(this);
+}
+
 } // namespace WebCore