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Adds interfaces, typemaps, and tests for collecting
StackSamplingProfiler result types. The collection interface will be
used to receive stack profiles from non-browser processes.

This change was previously reverted in
https://codereview.chromium.org/2264613002/ for introducing a skia
dependency that broke cronet. The dependency has been removed and the
new code has been split into independent targets.

BUG=517958

Committed: https://crrev.com/a6e65bb0cea385fc9fa82a5a1af4a5c3616e43e4
Review-Url: https://codereview.chromium.org/2253013008
Cr-Original-Commit-Position: refs/heads/master@{#413285}
Cr-Commit-Position: refs/heads/master@{#413471}