DO NOT SUBMIT really old prototype of sprite recognition for image replacement

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 1815328a24d6a0f9b4fd730bc7b10b6b36bcfe04..9e59568d34d6e814ad66e2ecd27042f28410de21 100644
--- a/third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp
+++ b/third_party/WebKit/Source/core/fetch/ImageResourceTest.cpp
@@ -30,6 +30,7 @@
 
 #include "core/fetch/ImageResource.h"
 
+#include "core/fetch/ImageResourceObserver.h"
 #include "core/fetch/MemoryCache.h"
 #include "core/fetch/MockResourceClients.h"
 #include "core/fetch/ResourceFetcher.h"
@@ -37,16 +38,21 @@
 #include "core/fetch/UniqueIdentifier.h"
 #include "platform/SharedBuffer.h"
 #include "platform/exported/WrappedResourceResponse.h"
+#include "platform/geometry/IntSize.h"
+#include "platform/graphics/BitmapImage.h"
 #include "platform/graphics/Image.h"
+#include "platform/network/ResourceError.h"
 #include "platform/scheduler/test/fake_web_task_runner.h"
 #include "platform/testing/URLTestHelpers.h"
 #include "platform/testing/UnitTestHelpers.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebCachePolicy.h"
 #include "public/platform/WebURL.h"
 #include "public/platform/WebURLLoaderMockFactory.h"
 #include "public/platform/WebURLResponse.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "wtf/PtrUtil.h"
+#include "wtf/text/Base64.h"
 #include <memory>
 
 namespace blink {
@@ -87,34 +93,36 @@ static Vector<unsigned char> jpegImage()
 }
 
 // An image of size 50x50.
+const char kJpegImage2Data[] = {
+    0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46, 0x00, 0x01, 0x01, 0x01, 0x00, 0x48,
+    0x00, 0x48, 0x00, 0x00, 0xff, 0xdb, 0x00, 0x43, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xdb, 0x00, 0x43, 0x01, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0,
+    0x00, 0x11, 0x08, 0x00, 0x32, 0x00, 0x32, 0x03, 0x01, 0x22, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11,
+    0x01, 0xff, 0xc4, 0x00, 0x14, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xc4, 0x00, 0x14, 0x10, 0x01, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xc4, 0x00,
+    0x15, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x02, 0xff, 0xc4, 0x00, 0x14, 0x11, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xda, 0x00, 0x0c, 0x03, 0x01,
+    0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00, 0x00, 0x94, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x03, 0xff, 0xd9
+};
+const int kJpegImage2Width = 50;
+const int kJpegImage2Height = 50;
+
+// An image of size 50x50.
 static Vector<unsigned char> jpegImage2()
 {
     Vector<unsigned char> jpeg;
-
-    static const unsigned char data[] = {
-        0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46, 0x00, 0x01, 0x01, 0x01, 0x00, 0x48,
-        0x00, 0x48, 0x00, 0x00, 0xff, 0xdb, 0x00, 0x43, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xdb, 0x00, 0x43, 0x01, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0,
-        0x00, 0x11, 0x08, 0x00, 0x32, 0x00, 0x32, 0x03, 0x01, 0x22, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11,
-        0x01, 0xff, 0xc4, 0x00, 0x14, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xc4, 0x00, 0x14, 0x10, 0x01, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xc4, 0x00,
-        0x15, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x02, 0xff, 0xc4, 0x00, 0x14, 0x11, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xda, 0x00, 0x0c, 0x03, 0x01,
-        0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00, 0x00, 0x94, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x03, 0xff, 0xd9
-    };
-
-    jpeg.append(data, sizeof(data));
+    jpeg.append(reinterpret_cast<const unsigned char*>(kJpegImage2Data), sizeof(kJpegImage2Data));
     return jpeg;
 }
 
@@ -637,4 +645,639 @@ TEST(ImageResourceTest, CancelOnDecodeError)
     EXPECT_FALSE(cachedImage->isLoading());
 }
 
+namespace {
+
+    // A subrange of |kJpegImage2Data| from which the image dimensions can be decoded.
+    const size_t kRangeWithDimensionsLength = arraysize(kJpegImage2Data) - 10;
+    static_assert(kRangeWithDimensionsLength < arraysize(kJpegImage2Data), "Sample image data is too short.");
+
+    TEST(ImageResourceTest, EnsureLongTestSubrangeContainsDimensions)
+    {
+        RefPtr<blink::Image> image = BitmapImage::create();
+        EXPECT_EQ(Image::SizeAvailable, image->setData(SharedBuffer::create(kJpegImage2Data, kRangeWithDimensionsLength), true));
+        EXPECT_EQ(kJpegImage2Width, image->width());
+        EXPECT_EQ(kJpegImage2Height, image->height());
+    }
+
+    // A subrange of |kJpegImage2Data| from which the image dimensions cannot be decoded.
+    const size_t kRangeWithoutDimensionsLength = 50;
+    static_assert(kRangeWithoutDimensionsLength < arraysize(kJpegImage2Data), "Sample image data is too short.");
+
+    TEST(ImageResourceTest, EnsureShortTestSubrangeDoesNotContainDimensions)
+    {
+        RefPtr<blink::Image> image = BitmapImage::create();
+        EXPECT_EQ(Image::SizeUnavailable, image->setData(SharedBuffer::create(kJpegImage2Data, kRangeWithoutDimensionsLength), true));
+    }
+
+    const char kPlaceholderForJpegImage2[] = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n"
+                                             "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"50\" height=\"50\">\n"
+                                             "<rect width=\"100%\" height=\"100%\" style=\"fill:rgba(127,127,127,0.4);stroke-width:2;stroke:black\" />\n"
+                                             "</svg>";
+
+    // A snapshot of some of the image-related state for an ImageResource.
+    struct ImageResourceSnapshot {
+        ImageResourceSnapshot()
+            : isNull(true)
+            , hasImage(false)
+            , dataLength(0)
+        {
+        }
+
+        ImageResourceSnapshot(ImageResource* image)
+            : isNull(false)
+            , hasImage(image->hasImage())
+            , dataLength(image->hasImage() && image->getImage()->data() ? image->getImage()->data()->size() : 0)
+            , dimensions(image->hasImage() ? image->getImage()->size() : IntSize())
+        {
+        }
+
+        ImageResourceSnapshot(bool hasImage,
+            size_t dataLength,
+            const IntSize& dimensions)
+            : isNull(false)
+            , hasImage(hasImage)
+            , dataLength(dataLength)
+            , dimensions(dimensions)
+        {
+        }
+
+        bool operator==(const ImageResourceSnapshot& other) const
+        {
+            return isNull == other.isNull && hasImage == other.hasImage && dataLength == other.dataLength && dimensions == other.dimensions;
+        }
+
+        bool isNull;
+        bool hasImage;
+        size_t dataLength;
+        IntSize dimensions;
+    };
+
+    // Implement the stream output operator so that ImageResourceSnapshots can be
+    // used with EXPECT_EQ.
+    std::ostream& operator<<(std::ostream& out, const ImageResourceSnapshot& snapshot)
+    {
+        return out << "{isNull:" << snapshot.isNull << ", hasImage:" << snapshot.hasImage << ", dataLength:" << snapshot.dataLength << ", dimensions:(" << snapshot.dimensions.width() << ';' << snapshot.dimensions.height() << ")}";
+    }
+
+    // An ImageResourceObserver that keeps track of the number of times
+    // imageChanged() and imageNotifyFinished() have been called, along with the
+    // ImageResourceSnapshot from the most recent call of each.
+    class TestImageResourceObserver : public GarbageCollectedFinalized<TestImageResourceObserver>, public ImageResourceObserver {
+        USING_PRE_FINALIZER(TestImageResourceObserver, dispose);
+
+    public:
+        explicit TestImageResourceObserver(ImageResource* image)
+            : m_image(image)
+            , m_imageChangedCount(0)
+            , m_imageNotifyFinishedCount(0)
+        {
+            image->addObserver(this);
+        }
+
+        ~TestImageResourceObserver() override;
+
+        DECLARE_TRACE();
+
+        void dispose()
+        {
+            if (m_image) {
+                m_image->removeObserver(this);
+                m_image = nullptr;
+            }
+        }
+
+        size_t imageChangedCount() const { return m_imageChangedCount; }
+        const ImageResourceSnapshot& lastImageChangedSnapshot() const { return m_lastImageChangedSnapshot; }
+        size_t imageNotifyFinishedCount() const { return m_imageNotifyFinishedCount; }
+        const ImageResourceSnapshot& lastImageNotifyFinishedSnapshot() const { return m_lastImageNotifyFinishedSnapshot; }
+
+    private:
+        void imageChanged(ImageResource* image, const IntRect* = 0) override
+        {
+            EXPECT_EQ(m_image.get(), image);
+            m_imageChangedCount++;
+            m_lastImageChangedSnapshot = ImageResourceSnapshot(image);
+        }
+
+        void imageNotifyFinished(ImageResource* image) override
+        {
+            EXPECT_EQ(m_image.get(), image);
+            m_imageNotifyFinishedCount++;
+            m_lastImageNotifyFinishedSnapshot = ImageResourceSnapshot(image);
+        }
+
+        bool willRenderImage() override { return true; }
+
+        String debugName() const override { return "TestImageResourceObserver"; }
+
+        Member<ImageResource> m_image;
+
+        size_t m_imageChangedCount;
+        ImageResourceSnapshot m_lastImageChangedSnapshot;
+        size_t m_imageNotifyFinishedCount;
+        ImageResourceSnapshot m_lastImageNotifyFinishedSnapshot;
+    };
+
+    TestImageResourceObserver::~TestImageResourceObserver() {}
+
+    DEFINE_TRACE(TestImageResourceObserver)
+    {
+        visitor->trace(m_image);
+    }
+
+    // Convenience class for registering and unregistering a mock load for a test
+    // URL.
+    class ScopedRegisteredURL {
+    public:
+        ScopedRegisteredURL(const KURL& url)
+            : m_url(url)
+        {
+            URLTestHelpers::registerMockedURLLoad(url, "cancelTest.html", "text/html");
+        }
+
+        ~ScopedRegisteredURL()
+        {
+            Platform::current()->getURLLoaderMockFactory()->unregisterURL(m_url);
+        }
+
+    private:
+        KURL m_url;
+    };
+
+    // Implement the stream output operator for WebCachePolicy so that it can be
+    // used with EXPECT_EQ.
+    std::ostream& operator<<(std::ostream& out, WebCachePolicy webCachePolicy)
+    {
+        return out << static_cast<int>(webCachePolicy);
+    }
+
+    static AtomicString buildContentRangeHeader(size_t rangeLength, size_t totalLength)
+    {
+        return AtomicString(String("bytes 0-" + String::number(rangeLength - 1) + "/" + String::number(totalLength)));
+    }
+
+    // Construct an "image/jpeg" response with the following properties.
+    static ResourceResponse buildImageResponse(const KURL& url, size_t length, int statusCode, const AtomicString& contentRangeHeader, bool wasCached)
+    {
+        ResourceResponse response(url, "image/jpeg", static_cast<long long>(length), nullAtom, String());
+        response.setHTTPStatusCode(statusCode);
+        if (!contentRangeHeader.isNull())
+            response.setHTTPHeaderField("content-range", contentRangeHeader);
+        response.setWasCached(wasCached);
+        return response;
+    }
+
+    // Use the |image|'s attached ResourceLoader to simulate the image receiving a response.
+    static void simulateImageLoad(ImageResource* image, const ResourceResponse& response, const char* data, size_t length)
+    {
+        const int intLength = safeCast<int>(length);
+        ResourceLoader* loader = image->loader();
+        loader->didReceiveResponse(nullptr, WrappedResourceResponse(response));
+        if (image->loader() == loader && data && length) {
+            loader->didReceiveData(nullptr, data, intLength, intLength, intLength);
+        }
+        if (image->loader() == loader) {
+            loader->didFinishLoading(nullptr, 0.0, intLength);
+        }
+    }
+
+    // Use the |image|'s attached ResourceLoader to simulate the image encountering an error.
+    static void simulateImageFailure(ImageResource* image, const ResourceError& error)
+    {
+        ResourceLoader* loader = image->loader();
+        loader->didFail(nullptr, error);
+        if (image->loader() == loader) {
+            loader->didFinishLoading(nullptr, 0.0, 0);
+        }
+    }
+
+    static void expectOriginalRequestIsForFullImage(ImageResource* image, int testId = 0)
+    {
+        EXPECT_EQ(nullAtom, image->getOriginalResourceRequest().httpHeaderField("range")) << testId;
+        EXPECT_EQ(WebCachePolicy::UseProtocolCachePolicy, image->getOriginalResourceRequest().getCachePolicy()) << testId;
+    }
+
+    static void expectLoadingFullImage(ImageResource* image, int testId = 0)
+    {
+        EXPECT_TRUE(image->isLoading()) << testId;
+        EXPECT_FALSE(image->isPlaceholder()) << testId;
+        EXPECT_EQ(nullAtom, image->resourceRequest().httpHeaderField("range")) << testId;
+        EXPECT_EQ(WebCachePolicy::UseProtocolCachePolicy, image->resourceRequest().getCachePolicy()) << testId;
+
+        expectOriginalRequestIsForFullImage(image, testId);
+    }
+
+    static void expectLoadingPlaceholder(ImageResource* image, int testId = 0)
+    {
+        EXPECT_TRUE(image->isLoading()) << testId;
+        EXPECT_TRUE(image->isPlaceholder()) << testId;
+        EXPECT_EQ("bytes=0-2047", image->resourceRequest().httpHeaderField("range")) << testId;
+        EXPECT_EQ(WebCachePolicy::UseProtocolCachePolicy, image->resourceRequest().getCachePolicy()) << testId;
+
+        expectOriginalRequestIsForFullImage(image, testId);
+    }
+
+    static void expectLoadingFullImageFromCache(ImageResource* image, int testId = 0)
+    {
+        EXPECT_TRUE(image->isLoading()) << testId;
+        EXPECT_TRUE(image->isPlaceholder()) << testId;
+        EXPECT_EQ(nullAtom, image->resourceRequest().httpHeaderField("range")) << testId;
+        EXPECT_EQ(WebCachePolicy::ReturnCacheDataDontLoad, image->resourceRequest().getCachePolicy()) << testId;
+
+        expectOriginalRequestIsForFullImage(image, testId);
+    }
+
+    static void expectLoadingFullImageBypassingCache(ImageResource* image, int testId = 0)
+    {
+        EXPECT_TRUE(image->isLoading()) << testId;
+        EXPECT_FALSE(image->isPlaceholder()) << testId;
+        EXPECT_EQ(nullAtom, image->resourceRequest().httpHeaderField("range")) << testId;
+        EXPECT_EQ(WebCachePolicy::BypassingCache, image->resourceRequest().getCachePolicy()) << testId;
+
+        expectOriginalRequestIsForFullImage(image, testId);
+    }
+
+    // Ensure that the current state of |image| and the most recent notifications
+    // sent to |observer| all match the given |expectedSnapshot|.
+    static void expectMatchesSnapshot(ImageResource* image, const TestImageResourceObserver& observer, const ImageResourceSnapshot& expectedSnapshot, int testId = 0)
+    {
+        EXPECT_EQ(expectedSnapshot, ImageResourceSnapshot(image)) << testId;
+        EXPECT_LT(0U, observer.imageChangedCount()) << testId;
+        EXPECT_EQ(expectedSnapshot, observer.lastImageChangedSnapshot()) << testId;
+        EXPECT_EQ(1U, observer.imageNotifyFinishedCount()) << testId;
+        EXPECT_EQ(expectedSnapshot, observer.lastImageNotifyFinishedSnapshot()) << testId;
+    }
+
+} // namespace
+
+TEST(ImageResourceTest, FetchImage)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    FetchRequest request(testURL, FetchInitiatorInfo());
+    ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()));
+    expectLoadingFullImage(image);
+
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+    simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, false), kJpegImage2Data, arraysize(kJpegImage2Data));
+
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_FALSE(image->isPlaceholder());
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)));
+}
+
+TEST(ImageResourceTest, FetchPlaceholderNotCached)
+{
+    AtomicString contentRangeHeaderOptions[] = {
+        buildContentRangeHeader(kRangeWithDimensionsLength, arraysize(kJpegImage2Data)),
+        "bogus content range",
+        AtomicString(String("bytes 1-" + String::number(kRangeWithDimensionsLength) + "/" + String::number(arraysize(kJpegImage2Data)))),
+        "bytes ",
+        "",
+    };
+    for (const AtomicString& contentRange : contentRangeHeaderOptions) {
+        const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+        ScopedRegisteredURL scopedTestLoad(testURL);
+        FetchRequest request(testURL, FetchInitiatorInfo());
+        ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+        expectLoadingPlaceholder(image);
+
+        TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+        simulateImageLoad(image, buildImageResponse(testURL, kRangeWithDimensionsLength, 206, contentRange, false), kJpegImage2Data, kRangeWithDimensionsLength);
+
+        EXPECT_EQ(Resource::Cached, image->getStatus());
+        EXPECT_TRUE(image->isPlaceholder());
+        expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, strlen(kPlaceholderForJpegImage2), IntSize(kJpegImage2Width, kJpegImage2Height)));
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderThenFetchFullAfterLoading)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/test_placeholder_image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    ResourceFetcher* fetcher = ResourceFetcher::create(ImageResourceTestMockFetchContext::create());
+    FetchRequest allowPlaceholderRequest(testURL, FetchInitiatorInfo());
+    ImageResource* image = ImageResource::fetch(allowPlaceholderRequest, fetcher, ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    expectLoadingPlaceholder(image);
+
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+    simulateImageLoad(image, buildImageResponse(testURL, kRangeWithDimensionsLength, 206, buildContentRangeHeader(kRangeWithDimensionsLength, arraysize(kJpegImage2Data)), false), kJpegImage2Data, kRangeWithDimensionsLength);
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_TRUE(image->isPlaceholder());
+
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, strlen(kPlaceholderForJpegImage2), IntSize(kJpegImage2Width, kJpegImage2Height)));
+    const ImageResourceSnapshot placeholderSnapshot(image);
+    EXPECT_EQ(1U, observer->imageNotifyFinishedCount());
+    EXPECT_EQ(placeholderSnapshot, observer->lastImageNotifyFinishedSnapshot());
+
+    FetchRequest disallowPlaceholderRequest(testURL, FetchInitiatorInfo());
+    ImageResource* fullImage = ImageResource::fetch(disallowPlaceholderRequest, fetcher, ImageResource::PlaceholderRequestType::DisallowPlaceholder);
+    EXPECT_EQ(image, fullImage);
+    expectLoadingFullImage(image);
+
+    simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, false), kJpegImage2Data, arraysize(kJpegImage2Data));
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+
+    const ImageResourceSnapshot expectedSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height));
+    EXPECT_EQ(expectedSnapshot, ImageResourceSnapshot(image));
+    EXPECT_LT(0U, observer->imageChangedCount());
+    EXPECT_EQ(expectedSnapshot, observer->lastImageChangedSnapshot());
+    EXPECT_EQ(1U, observer->imageNotifyFinishedCount());
+    EXPECT_EQ(placeholderSnapshot, observer->lastImageNotifyFinishedSnapshot());
+}
+
+TEST(ImageResourceTest, FetchPlaceholderThenFetchFullWhileLoading)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/test_placeholder_image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    FetchRequest allowPlaceholderRequest(testURL, FetchInitiatorInfo());
+    ResourceFetcher* fetcher = ResourceFetcher::create(ImageResourceTestMockFetchContext::create());
+    ImageResource* image = ImageResource::fetch(allowPlaceholderRequest, fetcher, ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    expectLoadingPlaceholder(image);
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+
+    FetchRequest disallowPlaceholderRequest(testURL, FetchInitiatorInfo());
+    ImageResource* fullImage = ImageResource::fetch(disallowPlaceholderRequest, fetcher, ImageResource::PlaceholderRequestType::DisallowPlaceholder);
+    EXPECT_EQ(image, fullImage);
+    expectLoadingFullImage(image);
+
+    simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, false), kJpegImage2Data, arraysize(kJpegImage2Data));
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_FALSE(image->isPlaceholder());
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)));
+}
+
+TEST(ImageResourceTest, FetchPlaceholderWith204)
+{
+    const bool wasCachedOptions[] = { false, true };
+    for (const auto& wasCached : wasCachedOptions) {
+        const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+        ScopedRegisteredURL scopedTestLoad(testURL);
+        FetchRequest request(testURL, FetchInitiatorInfo());
+        ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+        expectLoadingPlaceholder(image, &wasCached - wasCachedOptions);
+
+        TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+        simulateImageLoad(image, buildImageResponse(testURL, 0, 204, nullAtom, wasCached), nullptr, 0);
+
+        EXPECT_EQ(Resource::DecodeError, image->getStatus()) << (&wasCached - wasCachedOptions);
+        EXPECT_FALSE(image->isPlaceholder()) << (&wasCached - wasCachedOptions);
+        expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(false, 0, IntSize()), &wasCached - wasCachedOptions);
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderWithEntireResourceForRange)
+{
+    const bool wasCachedOptions[] = { false, true };
+    for (const auto& wasCached : wasCachedOptions) {
+        const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+        const ResourceResponse fullResponses[] = {
+            buildImageResponse(testURL, arraysize(kJpegImage2Data), 206, buildContentRangeHeader(arraysize(kJpegImage2Data), arraysize(kJpegImage2Data)), wasCached),
+            buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, wasCached),
+            buildImageResponse(testURL, arraysize(kJpegImage2Data), 404, nullAtom, wasCached),
+        };
+        for (const ResourceResponse& response : fullResponses) {
+            int testId = (&wasCached - wasCachedOptions) * arraysize(fullResponses) + (&response - fullResponses);
+            ScopedRegisteredURL scopedTestLoad(testURL);
+            FetchRequest request(testURL, FetchInitiatorInfo());
+            ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+            expectLoadingPlaceholder(image, testId);
+
+            TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+            simulateImageLoad(image, response, kJpegImage2Data, arraysize(kJpegImage2Data));
+
+            EXPECT_EQ(Resource::Cached, image->getStatus()) << testId;
+            EXPECT_FALSE(image->isPlaceholder()) << testId;
+            expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)), testId);
+        }
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderPartiallyCached)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    static const char kBadResponseData[] = "bad image response";
+
+    const struct {
+        ResourceError cacheError;
+        ResourceResponse cacheResponse;
+        const char* imageData;
+        size_t imageDataLength;
+    } tests[] = {
+        { ResourceError("net", -400, testURL, "Cache miss"), ResourceResponse(), nullptr, 0 },
+        { ResourceError(), buildImageResponse(testURL, arraysize(kBadResponseData), 200, nullAtom, true), kBadResponseData, arraysize(kBadResponseData) },
+        { ResourceError(), buildImageResponse(testURL, kRangeWithDimensionsLength, 206, buildContentRangeHeader(kRangeWithDimensionsLength, arraysize(kJpegImage2Data)), true), kJpegImage2Data, kRangeWithDimensionsLength },
+    };
+    for (const auto& test : tests) {
+        ScopedRegisteredURL scopedTestLoad(testURL);
+        FetchRequest request(testURL, FetchInitiatorInfo());
+        ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+        expectLoadingPlaceholder(image, &test - tests);
+
+        TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+        simulateImageLoad(image, buildImageResponse(testURL, kRangeWithDimensionsLength, 206, buildContentRangeHeader(kRangeWithDimensionsLength, arraysize(kJpegImage2Data)), true), kJpegImage2Data, kRangeWithDimensionsLength);
+        expectLoadingFullImageFromCache(image, &test - tests);
+
+        if (test.cacheError.isNull()) {
+            simulateImageLoad(image, test.cacheResponse, test.imageData, test.imageDataLength);
+        } else {
+            simulateImageFailure(image, test.cacheError);
+        }
+
+        EXPECT_EQ(Resource::Cached, image->getStatus()) << (&test - tests);
+        EXPECT_TRUE(image->isPlaceholder()) << (&test - tests);
+        EXPECT_FALSE(image->willPaintBrokenImage()) << (&test - tests);
+        expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, strlen(kPlaceholderForJpegImage2), IntSize(kJpegImage2Width, kJpegImage2Height)), &test - tests);
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderFullyCached)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    static const char kBadResponseData[] = "bad image response";
+
+    const struct {
+        ResourceResponse rangeResponse;
+        const char* imageData;
+        size_t imageDataLength;
+    } tests[] = {
+        { buildImageResponse(testURL, kRangeWithDimensionsLength, 206, buildContentRangeHeader(kRangeWithDimensionsLength, arraysize(kJpegImage2Data)), true), kJpegImage2Data, kRangeWithDimensionsLength },
+        { buildImageResponse(testURL, kRangeWithoutDimensionsLength, 206, buildContentRangeHeader(kRangeWithoutDimensionsLength, arraysize(kJpegImage2Data)), true), kJpegImage2Data, kRangeWithoutDimensionsLength },
+        { buildImageResponse(testURL, arraysize(kBadResponseData), 206, buildContentRangeHeader(arraysize(kBadResponseData), arraysize(kBadResponseData) + 10), true), kBadResponseData, arraysize(kBadResponseData) },
+    };
+    for (const auto& test : tests) {
+        ScopedRegisteredURL scopedTestLoad(testURL);
+        FetchRequest request(testURL, FetchInitiatorInfo());
+        ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+        expectLoadingPlaceholder(image, &test - tests);
+
+        TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+        simulateImageLoad(image, test.rangeResponse, test.imageData, test.imageDataLength);
+        expectLoadingFullImageFromCache(image, &test - tests);
+
+        simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, true), kJpegImage2Data, arraysize(kJpegImage2Data));
+        EXPECT_EQ(Resource::Cached, image->getStatus()) << (&test - tests);
+        EXPECT_FALSE(image->isPlaceholder()) << (&test - tests);
+        expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)), &test - tests);
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderFallbackToFullWithoutCacheCheck)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    static const char kBadResponseData[] = "bad image response";
+
+    const struct {
+        ResourceResponse rangeResponse;
+        const char* imageData;
+        size_t imageDataLength;
+    } tests[] = {
+        { buildImageResponse(testURL, kRangeWithoutDimensionsLength, 206, buildContentRangeHeader(kRangeWithoutDimensionsLength, arraysize(kJpegImage2Data)), false), kJpegImage2Data, kRangeWithoutDimensionsLength },
+        { buildImageResponse(testURL, arraysize(kBadResponseData), 206, buildContentRangeHeader(arraysize(kBadResponseData), arraysize(kBadResponseData) + 10), false), kBadResponseData, arraysize(kBadResponseData) },
+        { buildImageResponse(testURL, arraysize(kBadResponseData), 200, nullAtom, true), kBadResponseData, arraysize(kBadResponseData) },
+    };
+    for (const auto& test : tests) {
+        ScopedRegisteredURL scopedTestLoad(testURL);
+        FetchRequest request(testURL, FetchInitiatorInfo());
+        ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+        expectLoadingPlaceholder(image, &test - tests);
+
+        TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+        simulateImageLoad(image, test.rangeResponse, test.imageData, test.imageDataLength);
+        expectLoadingFullImageBypassingCache(image, &test - tests);
+
+        simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, false), kJpegImage2Data, arraysize(kJpegImage2Data));
+        EXPECT_EQ(Resource::Cached, image->getStatus()) << (&test - tests);
+        EXPECT_FALSE(image->isPlaceholder()) << (&test - tests);
+        expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)), &test - tests);
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderFallbackToFullWithCacheCheck)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    static const char kBadResponseData[] = "bad image response";
+
+    const struct {
+        ResourceResponse rangeResponse;
+        const char* imageData;
+        size_t imageDataLength;
+    } tests[] = {
+        { buildImageResponse(testURL, kRangeWithoutDimensionsLength, 206, buildContentRangeHeader(kRangeWithoutDimensionsLength, arraysize(kJpegImage2Data)), true), kJpegImage2Data, kRangeWithoutDimensionsLength },
+        { buildImageResponse(testURL, arraysize(kBadResponseData), 206, buildContentRangeHeader(arraysize(kBadResponseData), arraysize(kBadResponseData) + 10), true), kBadResponseData, arraysize(kBadResponseData) },
+    };
+    for (const auto& test : tests) {
+        ScopedRegisteredURL scopedTestLoad(testURL);
+        FetchRequest request(testURL, FetchInitiatorInfo());
+        ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+        expectLoadingPlaceholder(image, &test - tests);
+
+        TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+        simulateImageLoad(image, test.rangeResponse, test.imageData, test.imageDataLength);
+        expectLoadingFullImageFromCache(image, &test - tests);
+
+        simulateImageFailure(image, ResourceError("net", -400, testURL, "Cache miss"));
+        expectLoadingFullImageBypassingCache(image, &test - tests);
+
+        simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, false), kJpegImage2Data, arraysize(kJpegImage2Data));
+        EXPECT_EQ(Resource::Cached, image->getStatus()) << (&test - tests);
+        EXPECT_FALSE(image->isPlaceholder()) << (&test - tests);
+        expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)), &test - tests);
+    }
+}
+
+TEST(ImageResourceTest, FetchPlaceholderWithForcedCacheAndCachedRange)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    FetchRequest request(testURL, FetchInitiatorInfo());
+    request.mutableResourceRequest().setCachePolicy(WebCachePolicy::ReturnCacheDataDontLoad);
+    ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    EXPECT_TRUE(image->isLoading());
+    EXPECT_TRUE(image->isPlaceholder());
+    EXPECT_EQ("bytes=0-2047", image->resourceRequest().httpHeaderField("range"));
+    EXPECT_EQ(WebCachePolicy::ReturnCacheDataDontLoad, image->resourceRequest().getCachePolicy());
+
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+    simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 206, buildContentRangeHeader(kRangeWithDimensionsLength, arraysize(kJpegImage2Data)), true), kJpegImage2Data, kRangeWithDimensionsLength);
+    EXPECT_TRUE(image->isLoading());
+    EXPECT_TRUE(image->isPlaceholder());
+    EXPECT_EQ(WebCachePolicy::ReturnCacheDataDontLoad, image->resourceRequest().getCachePolicy());
+
+    simulateImageFailure(image, ResourceError("net", -400, testURL, "Cache miss"));
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_TRUE(image->isPlaceholder());
+
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, strlen(kPlaceholderForJpegImage2), IntSize(kJpegImage2Width, kJpegImage2Height)));
+}
+
+TEST(ImageResourceTest, FetchPlaceholderWithForcedCacheAndNoCachedRange)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    FetchRequest request(testURL, FetchInitiatorInfo());
+    request.mutableResourceRequest().setCachePolicy(WebCachePolicy::ReturnCacheDataDontLoad);
+    ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    EXPECT_TRUE(image->isLoading());
+    EXPECT_TRUE(image->isPlaceholder());
+    EXPECT_EQ("bytes=0-2047", image->resourceRequest().httpHeaderField("range"));
+    EXPECT_EQ(WebCachePolicy::ReturnCacheDataDontLoad, image->resourceRequest().getCachePolicy());
+
+    simulateImageFailure(image, ResourceError("net", -400, testURL, "Cache miss"));
+    EXPECT_FALSE(image->isLoading());
+    EXPECT_TRUE(image->willPaintBrokenImage());
+    EXPECT_FALSE(image->isPlaceholder());
+}
+
+TEST(ImageResourceTest, FetchDataURIAvoidsPlaceholder)
+{
+    const KURL testURL(ParsedURLString, String("data:image/jpeg;base64," + base64Encode(kJpegImage2Data, arraysize(kJpegImage2Data))));
+    FetchRequest request(testURL, FetchInitiatorInfo());
+    ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_FALSE(image->isPlaceholder());
+
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)));
+}
+
+TEST(ImageResourceTest, FetchWithPreexistingRangeHeaderAvoidsPlaceholder)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    FetchRequest request(testURL, FetchInitiatorInfo());
+    const AtomicString testRange(String("bytes=0-" + String::number(arraysize(kJpegImage2Data) - 1)));
+    request.mutableResourceRequest().setHTTPHeaderField("range", testRange);
+    ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    EXPECT_TRUE(image->isLoading());
+    EXPECT_FALSE(image->isPlaceholder());
+    EXPECT_EQ(testRange, image->resourceRequest().httpHeaderField("range"));
+
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+    simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 206, buildContentRangeHeader(arraysize(kJpegImage2Data), arraysize(kJpegImage2Data) + 10), false), kJpegImage2Data, arraysize(kJpegImage2Data));
+
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_FALSE(image->isPlaceholder());
+
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)));
+}
+
+TEST(ImageResourceTest, FetchWithPostRequestAvoidsPlaceholder)
+{
+    const KURL testURL(ParsedURLString, "http://www.test.com/image.jpg");
+    ScopedRegisteredURL scopedTestLoad(testURL);
+    FetchRequest request(testURL, FetchInitiatorInfo());
+    request.mutableResourceRequest().setHTTPMethod("POST");
+    ImageResource* image = ImageResource::fetch(request, ResourceFetcher::create(ImageResourceTestMockFetchContext::create()), ImageResource::PlaceholderRequestType::AllowPlaceholder);
+    expectLoadingFullImage(image);
+
+    TestImageResourceObserver* observer = new TestImageResourceObserver(image);
+    simulateImageLoad(image, buildImageResponse(testURL, arraysize(kJpegImage2Data), 200, nullAtom, false), kJpegImage2Data, arraysize(kJpegImage2Data));
+
+    EXPECT_EQ(Resource::Cached, image->getStatus());
+    EXPECT_FALSE(image->isPlaceholder());
+
+    expectMatchesSnapshot(image, *observer, ImageResourceSnapshot(true, arraysize(kJpegImage2Data), IntSize(kJpegImage2Width, kJpegImage2Height)));
+}
+
 } // namespace blink