Revert 226920 "Roll Clang 188423:191856."

trunk/src/base/debug/stack_trace_android.cc

Index: trunk/src/base/debug/stack_trace_android.cc
===================================================================
--- trunk/src/base/debug/stack_trace_android.cc	(revision 226977)
+++ trunk/src/base/debug/stack_trace_android.cc	(working copy)
@@ -26,6 +26,16 @@
   bool have_skipped_self;
 };
 
+// Clang's unwind.h doesn't provide _Unwind_GetIP on ARM, refer to
+// http://llvm.org/bugs/show_bug.cgi?id=16564 for details.
+#if defined(__clang__)
+uintptr_t _Unwind_GetIP(_Unwind_Context* context) {
+  uintptr_t ip = 0;
+  _Unwind_VRS_Get(context, _UVRSC_CORE, 15, _UVRSD_UINT32, &ip);
+  return ip & ~static_cast<uintptr_t>(0x1);  // Remove thumb mode bit.
+}
+#endif
+
 _Unwind_Reason_Code TraceStackFrame(_Unwind_Context* context, void* arg) {
   StackCrawlState* state = static_cast<StackCrawlState*>(arg);
   uintptr_t ip = _Unwind_GetIP(context);