Declare a new type for WeightDataSource

Maintaining both vector<HashStr> and unordered_map<HashStrView, V> for
lifecycle could be fragile.

Bug: 271527305
Test: NINJA_PRIORITY_FROM_BUILD_LOG=true m
Change-Id: Ic80c2b153b191fc2abd7ad2f0cb27a0f2d51cfa8
1 file changed