Make ImportedStyleSheetClient GarbageCollected

third_party/WebKit/Source/core/css/StyleRuleImport.cpp

Index: third_party/WebKit/Source/core/css/StyleRuleImport.cpp
diff --git a/third_party/WebKit/Source/core/css/StyleRuleImport.cpp b/third_party/WebKit/Source/core/css/StyleRuleImport.cpp
index 2bafa099f0efe3e97a819a5ba9595515e2f9d650..fce49e8554ac9b031461327acb7728c48786cd13 100644
--- a/third_party/WebKit/Source/core/css/StyleRuleImport.cpp
+++ b/third_party/WebKit/Source/core/css/StyleRuleImport.cpp
@@ -38,7 +38,7 @@ StyleRuleImport* StyleRuleImport::create(const String& href, MediaQuerySet* medi
 StyleRuleImport::StyleRuleImport(const String& href, MediaQuerySet* media)
     : StyleRuleBase(Import)
     , m_parentStyleSheet(nullptr)
-    , m_styleSheetClient(this)
+    , m_styleSheetClient(new ImportedStyleSheetClient(this))
     , m_strHref(href)
     , m_mediaQueries(media)
     , m_loading(false)
@@ -56,7 +56,7 @@ StyleRuleImport::~StyleRuleImport()
 void StyleRuleImport::dispose()
 {
     if (m_resource)
-        m_resource->removeClient(&m_styleSheetClient);
+        m_resource->removeClient(m_styleSheetClient);

[haraken, 2016/05/20 09:21:10]

Can you move this to a pre-finalizer of ImportedStyleSheetClient? (Then you can
remove a pre-finalizer from StyleRuleImport.)

The model is to let all resource clients remove itself from the owner resource
in their pre-finalizers (If the client inherits from ResourceOwner, the client
doesn't need to have a pre-finalizer).

[yhirano, 2016/05/23 11:29:05]

In this case StyleRuleImport has the resource and calls |addClient|, so it looks
natural to me that StyleRuleImport is responsible for removing the client from
the resource. It is possible to access the resource from the client
(m_owner->m_resource), but is it better than the current code?

     m_resource = nullptr;
 }
 
@@ -140,7 +140,7 @@ void StyleRuleImport::requestStyleSheet()
         if (m_parentStyleSheet && m_parentStyleSheet->loadCompleted() && rootSheet == m_parentStyleSheet)
             m_parentStyleSheet->startLoadingDynamicSheet();
         m_loading = true;
-        m_resource->addClient(&m_styleSheetClient);
+        m_resource->addClient(m_styleSheetClient);
     }
 }