Move RcuVector and relevant support classes to vespalib

Having RCU support available across all our C++ modules open up
new opportunities for optimizations.

This changes the following:
- `RcuVector` moved from `searchlib` to `vespalib`
- `MemoryUsage` moved from `searchlib` to `vespalib`
- Introduce a simplified, more generic `GrowStrategy` in `vespalib`
  used by the moved `RcuVector` which does not have any notion of
  documents. Existing searchlib `GrowStrategy` gets a simple function
  to convert to this generic strategy.

1 files changed, 2 insertions, 2 deletions

diff --git a/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp b/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp
index 436bfd97d8f..d636de46426 100644
--- a/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp
+++ b/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp
@@ -984,12 +984,12 @@ TEST_F("require that lid space can be compacted and shrunk", Fixture)
     EXPECT_FALSE(f.store.canShrinkLidSpace());
 
     f.compactLidSpace(2);
-    MemoryUsage before = f.store.getMemoryUsage();
+    vespalib::MemoryUsage before = f.store.getMemoryUsage();
     EXPECT_TRUE(f.store.canShrinkLidSpace());
     EXPECT_EQUAL(8u, f.store.getEstimatedShrinkLidSpaceGain()); // one lid info entry
     f.store.shrinkLidSpace();
 
-    MemoryUsage after = f.store.getMemoryUsage();
+    vespalib::MemoryUsage after = f.store.getMemoryUsage();
     EXPECT_LESS(after.usedBytes(), before.usedBytes());
     EXPECT_EQUAL(8u, before.usedBytes() - after.usedBytes());
 }