Add a StyleResourceClient in CSSStyleSheetResourceTest to keep Resource alive

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

Index: third_party/WebKit/Source/core/css/CSSStyleSheetResourceTest.cpp
diff --git a/third_party/WebKit/Source/core/css/CSSStyleSheetResourceTest.cpp b/third_party/WebKit/Source/core/css/CSSStyleSheetResourceTest.cpp
index c109a8594e3b04429a56c2dfffd54f57dd26684f..2eb757e418574eeed7f696446fc89df224753bc4 100644
--- a/third_party/WebKit/Source/core/css/CSSStyleSheetResourceTest.cpp
+++ b/third_party/WebKit/Source/core/css/CSSStyleSheetResourceTest.cpp
@@ -21,6 +21,7 @@
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/MemoryCache.h"
 #include "core/fetch/ResourceFetcher.h"
+#include "core/fetch/StyleSheetResourceClient.h"
 #include "core/testing/DummyPageHolder.h"
 #include "platform/heap/Handle.h"
 #include "platform/heap/Heap.h"
@@ -40,6 +41,11 @@ class Document;
 
 namespace {
 
+class MockStyleSheetResourceClient : public StyleSheetResourceClient {
+public:
+    String debugName() const override { return "MockStyleSheetResourceClient"; }
+};
+
 class CSSStyleSheetResourceTest : public ::testing::Test {
 protected:
     CSSStyleSheetResourceTest()
@@ -72,6 +78,8 @@ TEST_F(CSSStyleSheetResourceTest, PruneCanCauseEviction)
         document()->fetcher()->setAutoLoadImages(false);
 
         CSSStyleSheetResource* cssResource = CSSStyleSheetResource::createForTest(ResourceRequest(cssURL), "utf-8");
+        MockStyleSheetResourceClient client;
+        cssResource->addClient(&client);
         memoryCache()->add(cssResource);
         cssResource->responseReceived(ResourceResponse(cssURL, "style/css", 0, nullAtom, String()), nullptr);
         cssResource->finish();
@@ -112,6 +120,7 @@ TEST_F(CSSStyleSheetResourceTest, PruneCanCauseEviction)
                 memoryCache()->update(imageResource, imageResource->size(), imageResource->size(), true);
         }
         ASSERT_TRUE(memoryCache()->isInSameLRUListForTest(cssResource, imageResource));
+        cssResource->removeClient(&client);
     }
     ThreadHeap::collectAllGarbage();
     // This operation should not lead to crash!