Oilpan: eager resource disposal on MemoryCache eviction.

Promptly let go of a memory cache entry's Resource when evicting it,
and do not wait until the next GC to strike. This provides the same
behavior & lifetime for the resource as non-Oilpan.

R=mkwst
BUG=420068

Review URL: https://codereview.chromium.org/649213002

git-svn-id: svn://svn.chromium.org/blink/trunk@183606 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/fetch/MemoryCache.cpp

@@ -85,6 +85,13 @@ void MemoryCacheEntry::trace(Visitor* visitor)
     visitor->trace(m_nextInAllResourcesList);
 }
 
+#if ENABLE(OILPAN)
+void MemoryCacheEntry::dispose()
+{
+    m_resource.clear();
+}
+#endif
+
 void MemoryCacheLRUList::trace(Visitor* visitor)
 {
     visitor->trace(m_head);
@@ -372,11 +379,17 @@ bool MemoryCache::evict(MemoryCacheEntry* entry)
 
     ResourceMap::iterator it = m_resources.find(resource->url());
     ASSERT(it != m_resources.end());
-#if !ENABLE(OILPAN)
+#if ENABLE(OILPAN)
+    MemoryCacheEntry* entryPtr = it->value;
+#else
     OwnPtr<MemoryCacheEntry> entryPtr;
     entryPtr.swap(it->value);
 #endif
     m_resources.remove(it);
+#if ENABLE(OILPAN)
+    if (entryPtr)
+        entryPtr->dispose();
+#endif
     return canDelete;
 }
 

third_party/WebKit/Source/core/fetch/MemoryCache.h

@@ -74,8 +74,14 @@ enum UpdateReason {
 // from MemoryCacheLRUList.
 class MemoryCacheEntry final : public NoBaseWillBeGarbageCollectedFinalized<MemoryCacheEntry> {
 public:
-    static PassOwnPtrWillBeRawPtr<MemoryCacheEntry> create(Resource* resource) { return adoptPtrWillBeNoop(new MemoryCacheEntry(resource)); }
+    static PassOwnPtrWillBeRawPtr<MemoryCacheEntry> create(Resource* resource)
+    {
+        return adoptPtrWillBeNoop(new MemoryCacheEntry(resource));
+    }
     void trace(Visitor*);
+#if ENABLE(OILPAN)
+    void dispose();
+#endif
 
     ResourcePtr<Resource> m_resource;
     bool m_inLiveDecodedResourcesList;