simpleperf: don't expose libunwindstack in OfflineUnwinder.h.

It is to build etm decode library happen to include
OfflineUnwinder.h, but don't link with libunwindstack.

Bug: 135204414
Test: run simpleperf_unit_test.
Change-Id: I924498e7315b50ff44f85445f23c4be342bd39bd

1 files changed, 16 insertions, 0 deletions

diff --git a/simpleperf/nonlinux_support/nonlinux_support.cpp b/simpleperf/nonlinux_support/nonlinux_support.cpp
index 19a3cb11..1726b589 100644
--- a/simpleperf/nonlinux_support/nonlinux_support.cpp
+++ b/simpleperf/nonlinux_support/nonlinux_support.cpp
@@ -38,3 +38,19 @@ bool ReadSymbolsFromDexFile(const std::string&, const std::vector<uint64_t>&,
                             std::vector<DexFileSymbol>*) {
   return true;
 }
+
+namespace simpleperf {
+
+class DummyOfflineUnwinder : public OfflineUnwinder {
+ public:
+  bool UnwindCallChain(const ThreadEntry&, const RegSet&, const char*, size_t,
+                       std::vector<uint64_t>*, std::vector<uint64_t>*) override {
+    return false;
+  }
+};
+
+std::unique_ptr<OfflineUnwinder> OfflineUnwinder::Create(bool) {
+  return std::unique_ptr<OfflineUnwinder>(new DummyOfflineUnwinder);
+}
+
+}  // namespace simpleperf
\ No newline at end of file