Oilpan: Prepare to move Resource to Oilpan heap.

Source/core/fetch/MemoryCache.h

Index: Source/core/fetch/MemoryCache.h
diff --git a/Source/core/fetch/MemoryCache.h b/Source/core/fetch/MemoryCache.h
index e307ec372157e7ecd839788c453aa32d87b1eb08..47f203e4e06597edaeb4a1d53243e5928747e502 100644
--- a/Source/core/fetch/MemoryCache.h
+++ b/Source/core/fetch/MemoryCache.h
@@ -197,6 +197,11 @@ public:
     void makeLive(Resource*);
     void makeDead(Resource*);

[haraken, 2014/07/28 07:43:52]

Just help me understand: Do we need to distinguish makeLive/makeDead and
registerLiveResource/unregisterLiveResource? (i.e., what's a difference from the
perspective of when these methods are called?)

[tkent, 2014/07/28 08:14:19]

'Live' / 'Dead' in these functions mean 'has one or more ResourceClient or not'.
 It's different from Resource lifetime.  MemoryCache::m_allResources also has
different scope.

 
+    // This should be called when a Resource object is created.
+    void registerLiveResource(Resource&);
+    // This should be called when a Resource object becomes unnecesarry.
+    void unregisterLiveResource(Resource&);
+
     static void removeURLFromCache(ExecutionContext*, const KURL&);
 
     Statistics getStatistics();
@@ -274,6 +279,14 @@ private:
     typedef WillBeHeapHashMap<String, OwnPtrWillBeMember<MemoryCacheEntry> > ResourceMap;
     ResourceMap m_resources;
 
+#if ENABLE(OILPAN)
+    // Unlike m_allResources, m_liveResources is a set of Resource objects which
+    // should not be deleted. m_allResources only contains on-cache Resource
+    // objects.
+    // FIXME: Can we remove manual lifetime management of Resource and this?
+    HeapHashSet<Member<Resource> > m_liveResources;
+#endif
+
     friend class MemoryCacheTest;
 #ifdef MEMORY_CACHE_STATS
     Timer<MemoryCache> m_statsTimer;