Use common stack trace code in Android port

StackTrace has a common implementation (stack_trace.cc) as well as
platform specific ones (e.g, stack_strace_android.cc). This change makes
the Android port also use the common part instead of duplicating it.

This also fixes a Clang compilation failure due to the unused private
member variables.

Change-Id: I6ebb4815097b587cb4c6c639e5893f7759a3ff79
Reviewed-on: https://gerrit-int.chromium.org/21399
Reviewed-by: Marcus Bulach <bulach@google.com>
Tested-by: Sami Kyostila <skyostil@google.com>

BUG=
TEST=Build with clang and -Wunused-private-field


Review URL: https://chromiumcodereview.appspot.com/10702142

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@147424 0039d316-1c4b-4281-b951-d872f2087c98

base/base.gyp

@@ -139,7 +139,6 @@
             'USE_SYMBOLIZE',
           ],
           'sources!': [
-            'debug/stack_trace.cc',
             'debug/stack_trace_posix.cc',
           ],
         }],

base/debug/stack_trace_android.cc

@@ -16,17 +16,6 @@ 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.
@@ -55,10 +44,5 @@ void StackTrace::OutputToStream(std::ostream* os) const {
   NOTIMPLEMENTED();
 }
 
-std::string StackTrace::ToString() const {
-  NOTIMPLEMENTED();
-  return "";
-}
-
 }  // namespace debug
 }  // namespace base