Sub-task of bug 236754. We can simplify the inner workings of SourceBufferParserWebM by using SharedBuffer instead of building CMBlockBuffer progressively. We can reduce the amount of memory used as CMBlockBuffer always allocate more memory than is actually needed. It will also simplify the resolution of bug 236754.
<rdar://problem/89348752>
Created attachment 452964 [details] Patch
Created attachment 452967 [details] Patch for EWS
Created attachment 453094 [details] Patch
Created attachment 453095 [details] Patch for EWS
Created attachment 453138 [details] Patch
Created attachment 453139 [details] Patch
Created attachment 453163 [details] Patch for review
Created attachment 453164 [details] Patch
Committed r291020 (248194@main): <https://commits.webkit.org/248194@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 453163 [details].