Add StackVisitor, CountStackDepthVisitor, BuildStackTraceVisitor for EH.

In addition to EH, GC can use StackVisitor too.

Crawl stack in 2 passes, using CountStackDepthVisitor and
BuildStackTraceVisitor, respectively. Note that Pass 1 computes
the depth with a doubly-nested loop.

Change-Id: If1e3d3212037426b10ac5e6a01138acfab710e6b
3 files changed
tree: 8505c2429b204e799caa045bcb805e70e6e2ea87
  2. build/
  3. src/
  4. test/
  5. tools/