Use common stack trace code in Android port

base/debug/stack_trace_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/stack_trace.h"
 
 #include <signal.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "base/logging.h"
 
 namespace base {
 namespace debug {
 
 StackTrace::StackTrace() {
 }
 
-StackTrace::StackTrace(const void* const* trace, size_t count) {
-}
-
-StackTrace::~StackTrace() {
-}
-
-const void* const* StackTrace::Addresses(size_t* count) const {
-  NOTIMPLEMENTED();
-  return NULL;
-}
-
 // Sends fake SIGSTKFLT signals to let the Android linker and debuggerd dump
 // stack. See inlined comments and Android bionic/linker/debugger.c and
 // system/core/debuggerd/debuggerd.c for details.
 void StackTrace::PrintBacktrace() const {
   // Get the current handler of SIGSTKFLT for later use.
   sighandler_t sig_handler = signal(SIGSTKFLT, SIG_DFL);
   signal(SIGSTKFLT, sig_handler);
 
   // The Android linker will handle this signal and send a stack dumping request
   // to debuggerd which will ptrace_attach this process. Before returning from
   // the signal handler, the linker sets the signal handler to SIG_IGN.
   kill(gettid(), SIGSTKFLT);
 
   // Because debuggerd will wait for the process to be stopped by the actual
   // signal in crashing scenarios, signal is sent again to met the expectation.
   // Debuggerd will dump stack into the system log and /data/tombstones/ files.
   // NOTE: If this process runs in the interactive shell, it will be put
   // in the background. To resume it in the foreground, use 'fg' command.
   kill(gettid(), SIGSTKFLT);
 
   // Restore the signal handler so that this method can work the next time.
   signal(SIGSTKFLT, sig_handler);
 }
 
 void StackTrace::OutputToStream(std::ostream* os) const {
   NOTIMPLEMENTED();
 }
 
-std::string StackTrace::ToString() const {
-  NOTIMPLEMENTED();
-  return "";
-}
-
 }  // namespace debug
 }  // namespace base