Remove image/avif-sequence & avifs file extension

The AOMedia Image Working Group decided to remove the
"image/avif-sequence" MIME type and the "avifs" file extension from the
AVIF specification:
AOMediaCodec/av1-avif#59
AOMediaCodec/av1-avif#86

Since the future of the "image/avif-sequence" MIME type and the "avifs"
file extension is uncertain, it is best to remove them from the Chromium
source tree until the dust settles.

Test:
net_unittests --gtest_filter=MimeUtilTest.*
blink_common_unittests --disable-features=AVIF
blink_common_unittests --enable-features=AVIF
blink_platform_unittests --gtest_filter=*AVIF*

Bug: 1099839
Change-Id: I245e1ee2240bba315a49555908036eba7219afd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270670
Commit-Queue: Wan-Teh Chang 
Reviewed-by: Ryan Sleevi 
Reviewed-by: Peter Kasting 
Reviewed-by: Dale Curtis 
Cr-Commit-Position: refs/heads/master@{#783192}

Author: wantehchang

net/base/mime_util.cc

@@ -161,7 +161,6 @@ static const MimeInfo kPrimaryMappings[] = {
     {"audio/webm", "webm"},
     {"audio/x-m4a", "m4a"},
     {"image/avif", "avif"},
-    {"image/avif-sequence", "avifs"},
     {"image/gif", "gif"},
     {"image/jpeg", "jpeg,jpg"},
     {"image/png", "png"},
@@ -533,7 +532,6 @@ namespace {
 // From http://www.w3schools.com/media/media_mimeref.asp and
 // http://plugindoc.mozdev.org/winmime.php
 static const char* const kStandardImageTypes[] = {"image/avif",
-                                                  "image/avif-sequence"
                                                   "image/bmp",
                                                   "image/cis-cod",
                                                   "image/gif",

net/base/mime_util_unittest.cc

@@ -34,7 +34,6 @@ TEST(MimeUtilTest, ExtensionTest) {
     {FILE_PATH_LITERAL("webm"), "video/webm", true},
     {FILE_PATH_LITERAL("weba"), "audio/webm", true},
     {FILE_PATH_LITERAL("avif"), "image/avif", true},
-    {FILE_PATH_LITERAL("avifs"), "image/avif-sequence", true},
 #if defined(OS_CHROMEOS)
     // These are test cases for testing platform mime types on Chrome OS.
     {FILE_PATH_LITERAL("epub"), "application/epub+zip", true},
@@ -312,7 +311,6 @@ TEST(MimeUtilTest, TestGetExtensionsForMimeType) {
       {"MeSsAge/*", 1, "eml"},
       {"message/", 0, nullptr, true},
       {"image/avif", 1, "avif"},
-      {"image/avif-sequence", 1, "avifs"},
       {"image/bmp", 1, "bmp"},
       {"video/*", 6, "mp4"},
       {"video/*", 6, "mpeg"},

third_party/blink/common/mime_util/mime_util.cc

@@ -137,12 +137,10 @@ MimeUtil::MimeUtil() {
   for (const char* type : kSupportedImageTypes)
     image_types_.insert(type);
 #if BUILDFLAG(ENABLE_AV1_DECODER)
-  // TODO(wtc): Add "image/avif" and "image/avif-sequence" to the
-  // kSupportedImageTypes array when the AVIF feature is shipped.
-  if (base::FeatureList::IsEnabled(features::kAVIF)) {
+  // TODO(wtc): Add "image/avif" to the kSupportedImageTypes array when the AVIF
+  // feature is shipped.
+  if (base::FeatureList::IsEnabled(features::kAVIF))
     image_types_.insert("image/avif");
-    image_types_.insert("image/avif-sequence");
-  }
 #endif
   for (const char* type : kUnsupportedTextTypes)
     unsupported_text_types_.insert(type);

third_party/blink/common/mime_util/mime_util_unittest.cc

@@ -21,11 +21,8 @@ TEST(MimeUtilTest, LookupTypes) {
 #if BUILDFLAG(ENABLE_AV1_DECODER)
   EXPECT_EQ(IsSupportedImageMimeType("image/avif"),
             base::FeatureList::IsEnabled(features::kAVIF));
-  EXPECT_EQ(IsSupportedImageMimeType("image/avif-sequence"),
-            base::FeatureList::IsEnabled(features::kAVIF));
 #else
   EXPECT_FALSE(IsSupportedImageMimeType("image/avif"));
-  EXPECT_FALSE(IsSupportedImageMimeType("image/avif-sequence"));
 #endif
   EXPECT_FALSE(IsSupportedImageMimeType("image/lolcat"));
   EXPECT_FALSE(IsSupportedImageMimeType("Image/LolCat"));

third_party/blink/renderer/platform/image-decoders/avif/avif_image_decoder.cc

@@ -470,8 +470,8 @@ void AVIFImageDecoder::InitializeNewFrame(size_t index) {
 }
 
 void AVIFImageDecoder::Decode(size_t index) {
-  // TODO(dalecurtis): For fragmented avif-sequence files we probably want to
-  // allow partial decoding. Depends on if we see frequent use of multi-track
+  // TODO(dalecurtis): For fragmented AVIF image sequence files we probably want
+  // to allow partial decoding. Depends on if we see frequent use of multi-track
   // images where there's lots to ignore.
   if (Failed() || !IsAllDataReceived())
     return;

third_party/blink/renderer/platform/image-decoders/image_decoder.cc

@@ -141,7 +141,6 @@ String SniffMimeTypeInternal(scoped_refptr reader) {
 #if BUILDFLAG(ENABLE_AV1_DECODER)
   if (base::FeatureList::IsEnabled(features::kAVIF) &&
       AVIFImageDecoder::MatchesAVIFSignature(fast_reader)) {
-    // TODO(wtc): Sniff AVIF image sequences and return image/avif-sequence.
     return "image/avif";
   }
 #endif
@@ -305,8 +304,7 @@ ImageDecoder::CompressionFormat ImageDecoder::GetCompressionFormat(
   // TODO(wtc): Implement this. Figure out whether to return kUndefinedFormat or
   // a new kAVIFAnimationFormat in the case of an animated AVIF image.
   if (base::FeatureList::IsEnabled(features::kAVIF) &&
-      (EqualIgnoringASCIICase(mime_type, "image/avif") ||
-       EqualIgnoringASCIICase(mime_type, "image/avif-sequence"))) {
+      EqualIgnoringASCIICase(mime_type, "image/avif")) {
     return kLossyFormat;
   }
 #endif