disk_cache: Make GetAvailableRange reasonable to use safely.

Before this change, it took an out pointer parameter, which is really messy to manage destination lifetime for in a net-style method. (See the bug for a couple of different ways it could go wrong)

This change it to return (and pass to callbacks) the result by value instead, which avoids the complications entirely.


Bug: 1208738

Change-Id: I01f07ac693bb25266f91c3cd1ec4d69c023a1891
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2983259
Commit-Queue: Maksim Orlovich <morlovich@chromium.org>
Reviewed-by: Ben Kelly <wanderview@chromium.org>
Reviewed-by: Matthew Denton <mpdenton@chromium.org>
Reviewed-by: Shivani Sharma <shivanisha@chromium.org>
Cr-Commit-Position: refs/heads/master@{#898234}

• content/browser/cache_storage/cache_storage_cache_unittest.cc[diff]
• net/disk_cache/blockfile/entry_impl.cc[diff]
• net/disk_cache/blockfile/entry_impl.h[diff]
• net/disk_cache/blockfile/in_flight_backend_io.cc[diff]
• net/disk_cache/blockfile/in_flight_backend_io.h[diff]
• net/disk_cache/blockfile/sparse_control.cc[diff]
• net/disk_cache/blockfile/sparse_control.h[diff]
• net/disk_cache/disk_cache.h[diff]
• net/disk_cache/disk_cache_fuzzer.cc[diff]
• net/disk_cache/disk_cache_test_base.cc[diff]
• net/disk_cache/disk_cache_test_base.h[diff]
• net/disk_cache/disk_cache_test_util.cc[diff]
• net/disk_cache/disk_cache_test_util.h[diff]
• net/disk_cache/entry_unittest.cc[diff]
• net/disk_cache/memory/mem_entry_impl.cc[diff]
• net/disk_cache/memory/mem_entry_impl.h[diff]
• net/disk_cache/net_log_parameters.cc[diff]
• net/disk_cache/net_log_parameters.h[diff]
• net/disk_cache/simple/simple_entry_impl.cc[diff]
• net/disk_cache/simple/simple_entry_impl.h[diff]
• net/disk_cache/simple/simple_entry_operation.cc[diff]
• net/disk_cache/simple/simple_entry_operation.h[diff]
• net/disk_cache/simple/simple_synchronous_entry.cc[diff]
• net/disk_cache/simple/simple_synchronous_entry.h[diff]
• net/http/mock_http_cache.cc[diff]
• net/http/mock_http_cache.h[diff]
• net/http/partial_data.cc[diff]
• net/http/partial_data.h[diff]