Add image reading convenience methods

Summary:
These code changes add a couple convenience methods to remove/simplify common code patterns used when reading images that can be in unspecified image formats.
PixelFrame::readFrame can only read images that aren't image/video, because it doesn't know about image/video frames, but the new VideoRecordFormatStreamPlayer::readFrame can.
The benefit of these new helper functions can be seen in the other parts of code modified to use them. At the end of the day, the resulting code should do about the same thing.

Reviewed By: kiminoue7

Differential Revision: D51451623

fbshipit-source-id: 69ae21d1de140c8f22a8b5683a2be986bd59f6ee

csrc/reader/MultiVRSReader.cpp

@@ -210,14 +210,9 @@ bool OssMultiVRSReader::MultiVideoRecordFormatStreamPlayer::setBlock(
         record.reader->read(data);
         block.structuredArray = false;
       } else {
-        std::shared_ptr<utils::PixelFrame> frame;
-        bool frameValid;
-        if (contentBlock.image().getImageFormat() == vrs::ImageFormat::VIDEO) {
-          frame = make_shared<utils::PixelFrame>(contentBlock.image());
-          frameValid = (tryToDecodeFrame(*frame, record, contentBlock) == 0);
-        } else {
-          frameValid = utils::PixelFrame::readFrame(frame, record.reader, contentBlock);
-        }
+        std::shared_ptr<utils::PixelFrame> frame =
+            make_shared<utils::PixelFrame>(contentBlock.image());
+        bool frameValid = readFrame(*frame, record, contentBlock);
         if (XR_VERIFY(frameValid)) {
           block.structuredArray = true;
           // the image was read & maybe decompressed. Does it need to be converted, too?

csrc/reader/VRSReader.cpp

@@ -298,14 +298,8 @@ bool OssVRSReader::setBlock(
         record.reader->read(data);
         block.structuredArray = false;
       } else {
-        shared_ptr<utils::PixelFrame> frame;
-        bool frameValid;
-        if (contentBlock.image().getImageFormat() == ImageFormat::VIDEO) {
-          frame = make_shared<utils::PixelFrame>(contentBlock.image());
-          frameValid = (tryToDecodeFrame(*frame, record, contentBlock) == 0);
-        } else {
-          frameValid = utils::PixelFrame::readFrame(frame, record.reader, contentBlock);
-        }
+        shared_ptr<utils::PixelFrame> frame = make_shared<utils::PixelFrame>(contentBlock.image());
+        bool frameValid = readFrame(*frame, record, contentBlock);
         if (XR_VERIFY(frameValid)) {
           block.structuredArray = true;
           // the image was read & maybe decompressed. Does it need to be converted, too?