Add basic stacktrace handler using libunwind.

bench/benchmain.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "BenchTimer.h"
+#include "CrashHandler.h"
 #include "ResultsWriter.h"
 #include "SkBenchLogger.h"
 #include "SkBenchmark.h"
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkCommandLineFlags.h"
 #include "SkData.h"
 #include "SkDeferredCanvas.h"
 #include "SkGMBench.h"
@@ skipping 247 matching lines @@
     if (currRaw < FLAGS_minMs) {
         return false;
     }
     const double low = 1 - FLAGS_error, high = 1 + FLAGS_error;
     const double ratio = currPerLoop / prevPerLoop;
     return low < ratio && ratio < high;
 }
 
 int tool_main(int argc, char** argv);
 int tool_main(int argc, char** argv) {
+    SetupCrashHandler();
     SkCommandLineFlags::Parse(argc, argv);
 #if SK_ENABLE_INST_COUNT
     if (FLAGS_leaks) {
         gPrintInstCount = true;
     }
 #endif
     SkAutoGraphics ag;
 
     // First, parse some flags.
     SkBenchLogger logger;
@@ skipping 398 matching lines @@
     gContextFactory.destroyContexts();
 #endif
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif