Reland "Ensure |m_image| is (re-)created in ImageResource::didAddClient()"

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

Index: third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp
diff --git a/third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp b/third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp
index ea9494338d6da28d40408a3eae58b6524e0086ca..2df91c4d3206de10b4a08038fe5e021290a02099 100644
--- a/third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp
+++ b/third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp
@@ -307,4 +307,48 @@ TEST(ImageResourceTest, ReloadIfLoFi)
     ASSERT_TRUE(cachedImage->getImage()->isBitmapImage());
 }
 
+// Tests for pruning.
+
+TEST(ImageResourceTest, AddClientAfterPrune)
+{
+    KURL url(ParsedURLString, "http://127.0.0.1:8000/foo");
+    ImageResource* imageResource = ImageResource::create(ResourceRequest(url));
+
+    // Adds a ResourceClient but not ImageResourceObserver.
+    Persistent<MockResourceClient> client1 = new MockResourceClient(imageResource);
+
+    Vector<unsigned char> jpeg = jpegImage();
+    ResourceResponse response;
+    response.setURL(url);
+    response.setHTTPStatusCode(200);
+    response.setMimeType("image/jpeg");
+    imageResource->responseReceived(response, nullptr);
+    imageResource->appendData(reinterpret_cast<const char*>(jpeg.data()), jpeg.size());
+    imageResource->finish();
+
+    EXPECT_FALSE(imageResource->errorOccurred());
+    ASSERT_TRUE(imageResource->hasImage());
+    EXPECT_FALSE(imageResource->getImage()->isNull());
+    EXPECT_EQ(1, imageResource->getImage()->width());
+    EXPECT_EQ(1, imageResource->getImage()->height());
+    EXPECT_TRUE(client1->notifyFinishedCalled());
+
+    client1->removeAsClient();
+
+    EXPECT_FALSE(imageResource->hasClientsOrObservers());
+
+    imageResource->prune();
+
+    EXPECT_FALSE(imageResource->hasImage());
+
+    // Re-adds a ResourceClient but not ImageResourceObserver.
+    Persistent<MockResourceClient> client2 = new MockResourceClient(imageResource);
+
+    ASSERT_TRUE(imageResource->hasImage());
+    EXPECT_FALSE(imageResource->getImage()->isNull());
+    EXPECT_EQ(1, imageResource->getImage()->width());
+    EXPECT_EQ(1, imageResource->getImage()->height());
+    EXPECT_TRUE(client2->notifyFinishedCalled());
+}
+
 } // namespace blink