Bug fix: Fix wrong assumption in ImageResource when adding observer

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

 /*
  * Copyright (c) 2013, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 213 matching lines @@
     EXPECT_EQ("image/svg+xml", cachedImage->response().mimeType());
 
     const char secondPart[] = "<svg xmlns='http://www.w3.org/2000/svg' width='1' height='1'><rect width='1' height='1' fill='green'/></svg>\n";
     // The first bytes arrive. The data buffer is created, but no image is created.
     cachedImage->appendData(secondPart, strlen(secondPart));
     ASSERT_TRUE(cachedImage->resourceBuffer());
     ASSERT_FALSE(cachedImage->hasImage());
     ASSERT_EQ(client->imageChangedCount(), 0);
     ASSERT_FALSE(client->notifyFinishedCalled());
 
+    // Add a client to check an assertion error doesn't happen
+    // (crbug.com/630983).
+    Persistent<MockImageResourceClient> client2 = new MockImageResourceClient(cachedImage);
+    ASSERT_EQ(client2->imageChangedCount(), 0);
+    ASSERT_FALSE(client2->notifyFinishedCalled());
+
     const char thirdPart[] = "--boundary";
     cachedImage->appendData(thirdPart, strlen(thirdPart));
     ASSERT_TRUE(cachedImage->resourceBuffer());
     ASSERT_EQ(cachedImage->resourceBuffer()->size(), strlen(secondPart) - 1);
 
     // This part finishes. The image is created, callbacks are sent, and the data buffer is cleared.
     cachedImage->loader()->didFinishLoading(nullptr, 0.0, 0);
     ASSERT_TRUE(cachedImage->resourceBuffer());
     ASSERT_FALSE(cachedImage->errorOccurred());
     ASSERT_TRUE(cachedImage->hasImage());
     ASSERT_FALSE(cachedImage->getImage()->isNull());
     ASSERT_EQ(cachedImage->getImage()->width(), 1);
     ASSERT_EQ(cachedImage->getImage()->height(), 1);
     ASSERT_EQ(client->imageChangedCount(), 1);
     ASSERT_TRUE(client->notifyFinishedCalled());
+    ASSERT_EQ(client2->imageChangedCount(), 1);
+    ASSERT_TRUE(client2->notifyFinishedCalled());
 }
 
 TEST(ImageResourceTest, CancelOnDetach)
 {
     KURL testURL(ParsedURLString, "http://www.test.com/cancelTest.html");
     URLTestHelpers::registerMockedURLLoad(testURL, "cancelTest.html", "text/html");
 
     ResourceFetcher* fetcher = ResourceFetcher::create(ImageResourceTestMockFetchContext::create());
 
     // Emulate starting a real load.
@@ skipping 356 matching lines @@
     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