MemoryCache: make sure that Resources are evicted only when they can be deleted

Source/core/fetch/Resource.h

Index: Source/core/fetch/Resource.h
diff --git a/Source/core/fetch/Resource.h b/Source/core/fetch/Resource.h
index 3098eebb13406c0c9497eb91fc510b2d59520165..34b89278be995f26dc516dfe0ff2fed22c70e3d0 100644
--- a/Source/core/fetch/Resource.h
+++ b/Source/core/fetch/Resource.h
@@ -197,8 +197,8 @@ public:
     // Returns cached metadata of the given type associated with this resource.
     CachedMetadata* cachedMetadata(unsigned dataTypeID) const;
 
-    bool canDelete() const { return !hasClients() && !m_loader && !m_preloadCount && !m_handleCount && !m_protectorCount && !m_resourceToRevalidate && !m_proxyResource; }
-    bool hasOneHandle() const { return m_handleCount == 1; }
+    bool canDelete() const;
+    bool hasOneHandleApartFromCache() const;
 
     // List of acceptable MIME types separated by ",".
     // A MIME type may contain a wildcard, e.g. "text/*".
@@ -342,6 +342,8 @@ private:
 
     bool unlock();
 
+    bool hasRightHandleCountApartFromCache(unsigned targetCount) const;
+
     void failBeforeStarting();
 
     String m_fragmentIdentifierForRequest;