Register codecs with Skia explicitly (flutter/engine#42320)

In http://review.skia.org/689016, Skia added an option to explicitly
register codecs to use (instead of relying on #defines set by BUILD.gn
rules.

This uses that mechanism to explicitly register all the codecs that
Flutter was currently using from Skia (at least by my read of
[tools/gn](fee0534882/tools/gn (L292)).

I'm not sure if there is another place I need to put this sort of code,
e.g. for Fuchsia things.

To really test this out, we would want to add a define of
SK_DISABLE_LEGACY_INIT_DECODERS when compiling Skia, but I'm not sure
the best place to do this.

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- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I added new tests to check the change I am making or feature I am
adding, or Hixie said the PR is test-exempt. See [testing the engine]
for instructions on writing and running engine tests.
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engine/src/flutter/shell/common/shell.cc

@@ -29,6 +29,14 @@
 #include "rapidjson/stringbuffer.h"
 #include "rapidjson/writer.h"
 #include "third_party/dart/runtime/include/dart_tools_api.h"
+#include "third_party/skia/include/codec/SkBmpDecoder.h"
+#include "third_party/skia/include/codec/SkCodec.h"
+#include "third_party/skia/include/codec/SkGifDecoder.h"
+#include "third_party/skia/include/codec/SkIcoDecoder.h"
+#include "third_party/skia/include/codec/SkJpegDecoder.h"
+#include "third_party/skia/include/codec/SkPngDecoder.h"
+#include "third_party/skia/include/codec/SkWbmpDecoder.h"
+#include "third_party/skia/include/codec/SkWebpDecoder.h"
 #include "third_party/skia/include/core/SkGraphics.h"
 #include "third_party/skia/include/utils/SkBase64.h"
 #include "third_party/tonic/common/log.h"
@@ -74,6 +82,20 @@ std::unique_ptr<Engine> CreateEngine(
                                   gpu_disabled_switch);
 }
 
+void RegisterCodecsWithSkia() {
+  // These are in the order they will be attempted to be decoded from.
+  // If we have data to back it up, we can order these by "frequency used in
+  // the wild" for a very small performance bump, but for now we mirror the
+  // order Skia had them in.
+  SkCodecs::Register(SkPngDecoder::Decoder());
+  SkCodecs::Register(SkJpegDecoder::Decoder());
+  SkCodecs::Register(SkWebpDecoder::Decoder());
+  SkCodecs::Register(SkGifDecoder::Decoder());
+  SkCodecs::Register(SkBmpDecoder::Decoder());
+  SkCodecs::Register(SkWbmpDecoder::Decoder());
+  SkCodecs::Register(SkIcoDecoder::Decoder());
+}
+
 // Though there can be multiple shells, some settings apply to all components in
 // the process. These have to be set up before the shell or any of its
 // sub-components can be initialized. In a perfect world, this would be empty.
@@ -106,6 +128,7 @@ void PerformInitializationTasks(Settings& settings) {
     } else {
       FML_DLOG(INFO) << "Skia deterministic rendering is enabled.";
     }
+    RegisterCodecsWithSkia();
 
     if (settings.icu_initialization_required) {
       if (!settings.icu_data_path.empty()) {