Have uses of MockImageResourceClient leak less.

Source/core/frame/ImageBitmapTest.cpp

Index: Source/core/frame/ImageBitmapTest.cpp
diff --git a/Source/core/frame/ImageBitmapTest.cpp b/Source/core/frame/ImageBitmapTest.cpp
index 8f13a2806890f33ca7323c161b69b0aa442d6fa1..5f8593e2f1d95143a9baa751f4963775f62c5440 100644
--- a/Source/core/frame/ImageBitmapTest.cpp
+++ b/Source/core/frame/ImageBitmapTest.cpp
@@ -129,11 +129,10 @@ TEST_F(ImageBitmapTest, ImageBitmapLiveResourcePriority)
         StaticBitmapImage::create(m_image).get());
     imageOutsideCrop->setImageResource(cachedImageOutsideCrop.get());
 
-    MockImageResourceClient mockClient1, mockClient2, mockClient3, mockClient4;
-    cachedImageNoCrop->addClient(&mockClient1);
-    cachedImageInteriorCrop->addClient(&mockClient2);
-    cachedImageExteriorCrop->addClient(&mockClient3);
-    cachedImageOutsideCrop->addClient(&mockClient4);
+    MockImageResourceClient mockClient1(cachedImageNoCrop);
+    MockImageResourceClient mockClient2(cachedImageInteriorCrop);
+    MockImageResourceClient mockClient3(cachedImageExteriorCrop);
+    MockImageResourceClient mockClient4(cachedImageOutsideCrop);
 
     memoryCache()->add(cachedImageNoCrop.get());
     memoryCache()->add(cachedImageInteriorCrop.get());
@@ -181,11 +180,6 @@ TEST_F(ImageBitmapTest, ImageBitmapLiveResourcePriority)
     // There is still an ImageBitmap that references this image.
     ASSERT_EQ(memoryCache()->priority(imageInteriorCrop->cachedImage()), MemoryCacheLiveResourcePriorityHigh);
     imageBitmapInteriorCrop = nullptr;
-
-    cachedImageNoCrop->removeClient(&mockClient1);
-    cachedImageInteriorCrop->removeClient(&mockClient2);
-    cachedImageExteriorCrop->removeClient(&mockClient3);
-    cachedImageOutsideCrop->removeClient(&mockClient4);
 }
 
 // Verifies that ImageBitmaps constructed from HTMLImageElements hold a reference to the original Image if the HTMLImageElement src is changed.