third_party/blink/renderer/platform/image-decoders/image_decoder_test.cc - chromium/src - Git at Google

 /*
  * 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
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "third_party/blink/renderer/platform/image-decoders/image_decoder.h"

 #include <memory>
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/blink/renderer/platform/image-decoders/image_frame.h"
 #include "third_party/blink/renderer/platform/wtf/vector.h"

 namespace blink {

 class TestImageDecoder : public ImageDecoder {
  public:
   TestImageDecoder(
       ImageDecoder::HighBitDepthDecodingOption high_bit_depth_decoding_option)
       : ImageDecoder(kAlphaNotPremultiplied,
                      high_bit_depth_decoding_option,
                      ColorBehavior::TransformToSRGB(),
                      kNoDecodedImageByteLimit) {}

   TestImageDecoder() : TestImageDecoder(ImageDecoder::kDefaultBitDepth) {}

   String FilenameExtension() const override { return ""; }

   Vector<ImageFrame, 1>& FrameBufferCache() { return frame_buffer_cache_; }

   void ResetRequiredPreviousFrames(bool known_opaque = false) {
     for (size_t i = 0; i < frame_buffer_cache_.size(); ++i)
       frame_buffer_cache_[i].SetRequiredPreviousFrameIndex(
           FindRequiredPreviousFrame(i, known_opaque));
   }

   void InitFrames(size_t num_frames,
                   unsigned width = 100,
                   unsigned height = 100) {
     SetSize(width, height);
     frame_buffer_cache_.resize(num_frames);
     for (size_t i = 0; i < num_frames; ++i)
       frame_buffer_cache_[i].SetOriginalFrameRect(IntRect(0, 0, width, height));
   }

   bool ImageIsHighBitDepth() override { return image_is_high_bit_depth_; }
   void SetImageToHighBitDepthForTest() { image_is_high_bit_depth_ = true; }

  private:
   bool image_is_high_bit_depth_ = false;
   void DecodeSize() override {}
   void Decode(size_t index) override {}
 };

 TEST(ImageDecoderTest, sizeCalculationMayOverflow) {
   // Test coverage:
   // Regular bit depth image with regular decoder
   // Regular bit depth image with high bit depth decoder
   // High bit depth image with regular decoder
   // High bit depth image with high bit depth decoder
   bool high_bit_depth_decoder_status[] = {false, true};
   bool high_bit_depth_image_status[] = {false, true};

   for (bool high_bit_depth_decoder : high_bit_depth_decoder_status) {
     for (bool high_bit_depth_image : high_bit_depth_image_status) {
       std::unique_ptr<TestImageDecoder> decoder;
       if (high_bit_depth_decoder) {
         decoder = std::make_unique<TestImageDecoder>(
             ImageDecoder::kHighBitDepthToHalfFloat);
       } else {
         decoder = std::make_unique<TestImageDecoder>();
       }
       if (high_bit_depth_image)
         decoder->SetImageToHighBitDepthForTest();

       unsigned log_pixel_size = 2;  // pixel is 4 bytes
       if (high_bit_depth_decoder && high_bit_depth_image)
         log_pixel_size = 3;  // pixel is 8 byts
       unsigned overflow_dim_shift = 31 - log_pixel_size;
       unsigned overflow_dim_shift_half = (overflow_dim_shift + 1) / 2;

       EXPECT_FALSE(decoder->SetSize(1 << overflow_dim_shift, 1));
       EXPECT_FALSE(decoder->SetSize(1, 1 << overflow_dim_shift));
       EXPECT_FALSE(decoder->SetSize(1 << overflow_dim_shift_half,
                                     1 << overflow_dim_shift_half));
       EXPECT_TRUE(decoder->SetSize(1 << (overflow_dim_shift - 1), 1));
       EXPECT_TRUE(decoder->SetSize(1, 1 << (overflow_dim_shift - 1)));
       EXPECT_TRUE(decoder->SetSize(1 << (overflow_dim_shift_half - 1),
                                    1 << (overflow_dim_shift_half - 1)));
     }
   }
 }

 TEST(ImageDecoderTest, requiredPreviousFrameIndex) {
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(6);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

   frame_buffers[1].SetDisposalMethod(ImageFrame::kDisposeKeep);
   frame_buffers[2].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
   frame_buffers[3].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
   frame_buffers[4].SetDisposalMethod(ImageFrame::kDisposeKeep);

   decoder->ResetRequiredPreviousFrames();

   // The first frame doesn't require any previous frame.
   EXPECT_EQ(kNotFound, frame_buffers[0].RequiredPreviousFrameIndex());
   // The previous DisposeNotSpecified frame is required.
   EXPECT_EQ(0u, frame_buffers[1].RequiredPreviousFrameIndex());
   // DisposeKeep is treated as DisposeNotSpecified.
   EXPECT_EQ(1u, frame_buffers[2].RequiredPreviousFrameIndex());
   // Previous DisposeOverwritePrevious frames are skipped.
   EXPECT_EQ(1u, frame_buffers[3].RequiredPreviousFrameIndex());
   EXPECT_EQ(1u, frame_buffers[4].RequiredPreviousFrameIndex());
   EXPECT_EQ(4u, frame_buffers[5].RequiredPreviousFrameIndex());
 }

 TEST(ImageDecoderTest, requiredPreviousFrameIndexDisposeOverwriteBgcolor) {
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(3);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

   // Fully covering DisposeOverwriteBgcolor previous frame resets the starting
   // state.
   frame_buffers[1].SetDisposalMethod(ImageFrame::kDisposeOverwriteBgcolor);
   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());

   // Partially covering DisposeOverwriteBgcolor previous frame is required by
   // this frame.
   frame_buffers[1].SetOriginalFrameRect(IntRect(50, 50, 50, 50));
   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(1u, frame_buffers[2].RequiredPreviousFrameIndex());
 }

 TEST(ImageDecoderTest, requiredPreviousFrameIndexForFrame1) {
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(2);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(0u, frame_buffers[1].RequiredPreviousFrameIndex());

   // The first frame with DisposeOverwritePrevious or DisposeOverwriteBgcolor
   // resets the starting state.
   frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());
   frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwriteBgcolor);
   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());

   // ... even if it partially covers.
   frame_buffers[0].SetOriginalFrameRect(IntRect(50, 50, 50, 50));

   frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());
   frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwriteBgcolor);
   decoder->ResetRequiredPreviousFrames();
   EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());
 }

 TEST(ImageDecoderTest, requiredPreviousFrameIndexBlendAtopBgcolor) {
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(3);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

   frame_buffers[1].SetOriginalFrameRect(IntRect(25, 25, 50, 50));
   frame_buffers[2].SetAlphaBlendSource(ImageFrame::kBlendAtopBgcolor);

   // A full frame with 'blending method == BlendAtopBgcolor' doesn't depend on
   // any prior frames.
   for (int dispose_method = ImageFrame::kDisposeNotSpecified;
        dispose_method <= ImageFrame::kDisposeOverwritePrevious;
        ++dispose_method) {
     frame_buffers[1].SetDisposalMethod(
         static_cast<ImageFrame::DisposalMethod>(dispose_method));
     decoder->ResetRequiredPreviousFrames();
     EXPECT_EQ(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
   }

   // A non-full frame with 'blending method == BlendAtopBgcolor' does depend on
   // a prior frame.
   frame_buffers[2].SetOriginalFrameRect(IntRect(50, 50, 50, 50));
   for (int dispose_method = ImageFrame::kDisposeNotSpecified;
        dispose_method <= ImageFrame::kDisposeOverwritePrevious;
        ++dispose_method) {
     frame_buffers[1].SetDisposalMethod(
         static_cast<ImageFrame::DisposalMethod>(dispose_method));
     decoder->ResetRequiredPreviousFrames();
     EXPECT_NE(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
   }
 }

 TEST(ImageDecoderTest, requiredPreviousFrameIndexKnownOpaque) {
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(3);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

   frame_buffers[1].SetOriginalFrameRect(IntRect(25, 25, 50, 50));

   // A full frame that is known to be opaque doesn't depend on any prior frames.
   for (int dispose_method = ImageFrame::kDisposeNotSpecified;
        dispose_method <= ImageFrame::kDisposeOverwritePrevious;
        ++dispose_method) {
     frame_buffers[1].SetDisposalMethod(
         static_cast<ImageFrame::DisposalMethod>(dispose_method));
     decoder->ResetRequiredPreviousFrames(true);
     EXPECT_EQ(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
   }

   // A non-full frame that is known to be opaque does depend on a prior frame.
   frame_buffers[2].SetOriginalFrameRect(IntRect(50, 50, 50, 50));
   for (int dispose_method = ImageFrame::kDisposeNotSpecified;
        dispose_method <= ImageFrame::kDisposeOverwritePrevious;
        ++dispose_method) {
     frame_buffers[1].SetDisposalMethod(
         static_cast<ImageFrame::DisposalMethod>(dispose_method));
     decoder->ResetRequiredPreviousFrames(true);
     EXPECT_NE(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
   }
 }

 TEST(ImageDecoderTest, clearCacheExceptFrameDoNothing) {
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->ClearCacheExceptFrame(0);

   // This should not crash.
   decoder->InitFrames(20);
   decoder->ClearCacheExceptFrame(kNotFound);
 }

 TEST(ImageDecoderTest, clearCacheExceptFrameAll) {
   const size_t kNumFrames = 10;
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(kNumFrames);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();
   for (size_t i = 0; i < kNumFrames; ++i)
     frame_buffers[i].SetStatus(i % 2 ? ImageFrame::kFramePartial
                                      : ImageFrame::kFrameComplete);

   decoder->ClearCacheExceptFrame(kNotFound);

   for (size_t i = 0; i < kNumFrames; ++i) {
     SCOPED_TRACE(testing::Message() << i);
     EXPECT_EQ(ImageFrame::kFrameEmpty, frame_buffers[i].GetStatus());
   }
 }

 TEST(ImageDecoderTest, clearCacheExceptFramePreverveClearExceptFrame) {
   const size_t kNumFrames = 10;
   std::unique_ptr<TestImageDecoder> decoder(
       std::make_unique<TestImageDecoder>());
   decoder->InitFrames(kNumFrames);
   Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();
   for (size_t i = 0; i < kNumFrames; ++i)
     frame_buffers[i].SetStatus(ImageFrame::kFrameComplete);

   decoder->ResetRequiredPreviousFrames();
   decoder->ClearCacheExceptFrame(5);
   for (size_t i = 0; i < kNumFrames; ++i) {
     SCOPED_TRACE(testing::Message() << i);
     if (i == 5)
       EXPECT_EQ(ImageFrame::kFrameComplete, frame_buffers[i].GetStatus());
     else
       EXPECT_EQ(ImageFrame::kFrameEmpty, frame_buffers[i].GetStatus());
   }
 }

 }  // namespace blink
	/*
	* 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
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "third_party/blink/renderer/platform/image-decoders/image_decoder.h"

	#include <memory>
	#include "testing/gtest/include/gtest/gtest.h"
	#include "third_party/blink/renderer/platform/image-decoders/image_frame.h"
	#include "third_party/blink/renderer/platform/wtf/vector.h"

	namespace blink {

	class TestImageDecoder : public ImageDecoder {
	public:
	TestImageDecoder(
	ImageDecoder::HighBitDepthDecodingOption high_bit_depth_decoding_option)
	: ImageDecoder(kAlphaNotPremultiplied,
	high_bit_depth_decoding_option,
	ColorBehavior::TransformToSRGB(),
	kNoDecodedImageByteLimit) {}

	TestImageDecoder() : TestImageDecoder(ImageDecoder::kDefaultBitDepth) {}

	String FilenameExtension() const override { return ""; }

	Vector<ImageFrame, 1>& FrameBufferCache() { return frame_buffer_cache_; }

	void ResetRequiredPreviousFrames(bool known_opaque = false) {
	for (size_t i = 0; i < frame_buffer_cache_.size(); ++i)
	frame_buffer_cache_[i].SetRequiredPreviousFrameIndex(
	FindRequiredPreviousFrame(i, known_opaque));
	}

	void InitFrames(size_t num_frames,
	unsigned width = 100,
	unsigned height = 100) {
	SetSize(width, height);
	frame_buffer_cache_.resize(num_frames);
	for (size_t i = 0; i < num_frames; ++i)
	frame_buffer_cache_[i].SetOriginalFrameRect(IntRect(0, 0, width, height));
	}

	bool ImageIsHighBitDepth() override { return image_is_high_bit_depth_; }
	void SetImageToHighBitDepthForTest() { image_is_high_bit_depth_ = true; }

	private:
	bool image_is_high_bit_depth_ = false;
	void DecodeSize() override {}
	void Decode(size_t index) override {}
	};

	TEST(ImageDecoderTest, sizeCalculationMayOverflow) {
	// Test coverage:
	// Regular bit depth image with regular decoder
	// Regular bit depth image with high bit depth decoder
	// High bit depth image with regular decoder
	// High bit depth image with high bit depth decoder
	bool high_bit_depth_decoder_status[] = {false, true};
	bool high_bit_depth_image_status[] = {false, true};

	for (bool high_bit_depth_decoder : high_bit_depth_decoder_status) {
	for (bool high_bit_depth_image : high_bit_depth_image_status) {
	std::unique_ptr<TestImageDecoder> decoder;
	if (high_bit_depth_decoder) {
	decoder = std::make_unique<TestImageDecoder>(
	ImageDecoder::kHighBitDepthToHalfFloat);
	} else {
	decoder = std::make_unique<TestImageDecoder>();
	}
	if (high_bit_depth_image)
	decoder->SetImageToHighBitDepthForTest();

	unsigned log_pixel_size = 2; // pixel is 4 bytes
	if (high_bit_depth_decoder && high_bit_depth_image)
	log_pixel_size = 3; // pixel is 8 byts
	unsigned overflow_dim_shift = 31 - log_pixel_size;
	unsigned overflow_dim_shift_half = (overflow_dim_shift + 1) / 2;

	EXPECT_FALSE(decoder->SetSize(1 << overflow_dim_shift, 1));
	EXPECT_FALSE(decoder->SetSize(1, 1 << overflow_dim_shift));
	EXPECT_FALSE(decoder->SetSize(1 << overflow_dim_shift_half,
	1 << overflow_dim_shift_half));
	EXPECT_TRUE(decoder->SetSize(1 << (overflow_dim_shift - 1), 1));
	EXPECT_TRUE(decoder->SetSize(1, 1 << (overflow_dim_shift - 1)));
	EXPECT_TRUE(decoder->SetSize(1 << (overflow_dim_shift_half - 1),
	1 << (overflow_dim_shift_half - 1)));
	}
	}
	}

	TEST(ImageDecoderTest, requiredPreviousFrameIndex) {
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(6);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

	frame_buffers[1].SetDisposalMethod(ImageFrame::kDisposeKeep);
	frame_buffers[2].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
	frame_buffers[3].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
	frame_buffers[4].SetDisposalMethod(ImageFrame::kDisposeKeep);

	decoder->ResetRequiredPreviousFrames();

	// The first frame doesn't require any previous frame.
	EXPECT_EQ(kNotFound, frame_buffers[0].RequiredPreviousFrameIndex());
	// The previous DisposeNotSpecified frame is required.
	EXPECT_EQ(0u, frame_buffers[1].RequiredPreviousFrameIndex());
	// DisposeKeep is treated as DisposeNotSpecified.
	EXPECT_EQ(1u, frame_buffers[2].RequiredPreviousFrameIndex());
	// Previous DisposeOverwritePrevious frames are skipped.
	EXPECT_EQ(1u, frame_buffers[3].RequiredPreviousFrameIndex());
	EXPECT_EQ(1u, frame_buffers[4].RequiredPreviousFrameIndex());
	EXPECT_EQ(4u, frame_buffers[5].RequiredPreviousFrameIndex());
	}

	TEST(ImageDecoderTest, requiredPreviousFrameIndexDisposeOverwriteBgcolor) {
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(3);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

	// Fully covering DisposeOverwriteBgcolor previous frame resets the starting
	// state.
	frame_buffers[1].SetDisposalMethod(ImageFrame::kDisposeOverwriteBgcolor);
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());

	// Partially covering DisposeOverwriteBgcolor previous frame is required by
	// this frame.
	frame_buffers[1].SetOriginalFrameRect(IntRect(50, 50, 50, 50));
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(1u, frame_buffers[2].RequiredPreviousFrameIndex());
	}

	TEST(ImageDecoderTest, requiredPreviousFrameIndexForFrame1) {
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(2);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(0u, frame_buffers[1].RequiredPreviousFrameIndex());

	// The first frame with DisposeOverwritePrevious or DisposeOverwriteBgcolor
	// resets the starting state.
	frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());
	frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwriteBgcolor);
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());

	// ... even if it partially covers.
	frame_buffers[0].SetOriginalFrameRect(IntRect(50, 50, 50, 50));

	frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwritePrevious);
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());
	frame_buffers[0].SetDisposalMethod(ImageFrame::kDisposeOverwriteBgcolor);
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(kNotFound, frame_buffers[1].RequiredPreviousFrameIndex());
	}

	TEST(ImageDecoderTest, requiredPreviousFrameIndexBlendAtopBgcolor) {
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(3);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

	frame_buffers[1].SetOriginalFrameRect(IntRect(25, 25, 50, 50));
	frame_buffers[2].SetAlphaBlendSource(ImageFrame::kBlendAtopBgcolor);

	// A full frame with 'blending method == BlendAtopBgcolor' doesn't depend on
	// any prior frames.
	for (int dispose_method = ImageFrame::kDisposeNotSpecified;
	dispose_method <= ImageFrame::kDisposeOverwritePrevious;
	++dispose_method) {
	frame_buffers[1].SetDisposalMethod(
	static_cast<ImageFrame::DisposalMethod>(dispose_method));
	decoder->ResetRequiredPreviousFrames();
	EXPECT_EQ(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
	}

	// A non-full frame with 'blending method == BlendAtopBgcolor' does depend on
	// a prior frame.
	frame_buffers[2].SetOriginalFrameRect(IntRect(50, 50, 50, 50));
	for (int dispose_method = ImageFrame::kDisposeNotSpecified;
	dispose_method <= ImageFrame::kDisposeOverwritePrevious;
	++dispose_method) {
	frame_buffers[1].SetDisposalMethod(
	static_cast<ImageFrame::DisposalMethod>(dispose_method));
	decoder->ResetRequiredPreviousFrames();
	EXPECT_NE(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
	}
	}

	TEST(ImageDecoderTest, requiredPreviousFrameIndexKnownOpaque) {
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(3);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();

	frame_buffers[1].SetOriginalFrameRect(IntRect(25, 25, 50, 50));

	// A full frame that is known to be opaque doesn't depend on any prior frames.
	for (int dispose_method = ImageFrame::kDisposeNotSpecified;
	dispose_method <= ImageFrame::kDisposeOverwritePrevious;
	++dispose_method) {
	frame_buffers[1].SetDisposalMethod(
	static_cast<ImageFrame::DisposalMethod>(dispose_method));
	decoder->ResetRequiredPreviousFrames(true);
	EXPECT_EQ(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
	}

	// A non-full frame that is known to be opaque does depend on a prior frame.
	frame_buffers[2].SetOriginalFrameRect(IntRect(50, 50, 50, 50));
	for (int dispose_method = ImageFrame::kDisposeNotSpecified;
	dispose_method <= ImageFrame::kDisposeOverwritePrevious;
	++dispose_method) {
	frame_buffers[1].SetDisposalMethod(
	static_cast<ImageFrame::DisposalMethod>(dispose_method));
	decoder->ResetRequiredPreviousFrames(true);
	EXPECT_NE(kNotFound, frame_buffers[2].RequiredPreviousFrameIndex());
	}
	}

	TEST(ImageDecoderTest, clearCacheExceptFrameDoNothing) {
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->ClearCacheExceptFrame(0);

	// This should not crash.
	decoder->InitFrames(20);
	decoder->ClearCacheExceptFrame(kNotFound);
	}

	TEST(ImageDecoderTest, clearCacheExceptFrameAll) {
	const size_t kNumFrames = 10;
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(kNumFrames);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();
	for (size_t i = 0; i < kNumFrames; ++i)
	frame_buffers[i].SetStatus(i % 2 ? ImageFrame::kFramePartial
	: ImageFrame::kFrameComplete);

	decoder->ClearCacheExceptFrame(kNotFound);

	for (size_t i = 0; i < kNumFrames; ++i) {
	SCOPED_TRACE(testing::Message() << i);
	EXPECT_EQ(ImageFrame::kFrameEmpty, frame_buffers[i].GetStatus());
	}
	}

	TEST(ImageDecoderTest, clearCacheExceptFramePreverveClearExceptFrame) {
	const size_t kNumFrames = 10;
	std::unique_ptr<TestImageDecoder> decoder(
	std::make_unique<TestImageDecoder>());
	decoder->InitFrames(kNumFrames);
	Vector<ImageFrame, 1>& frame_buffers = decoder->FrameBufferCache();
	for (size_t i = 0; i < kNumFrames; ++i)
	frame_buffers[i].SetStatus(ImageFrame::kFrameComplete);

	decoder->ResetRequiredPreviousFrames();
	decoder->ClearCacheExceptFrame(5);
	for (size_t i = 0; i < kNumFrames; ++i) {
	SCOPED_TRACE(testing::Message() << i);
	if (i == 5)
	EXPECT_EQ(ImageFrame::kFrameComplete, frame_buffers[i].GetStatus());
	else
	EXPECT_EQ(ImageFrame::kFrameEmpty, frame_buffers[i].GetStatus());
	}
	}

	} // namespace blink