Revert of Cleaner fall-back stack capture for --enable-heap-profiling=native.

base/trace_event/heap_profiler_allocation_context_tracker.cc

 // Copyright 2015 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/trace_event/heap_profiler_allocation_context_tracker.h"
 
 #include <algorithm>
 #include <iterator>
 
 #include "base/atomicops.h"
@@ skipping 185 matching lines @@
               StackFrame::FromTraceEventName(stack_frame.trace_event_name);
         }
         break;
       }
     case CaptureMode::NATIVE_STACK:
       {
         // Backtrace contract requires us to return bottom frames, i.e.
         // from main() and up. Stack unwinding produces top frames, i.e.
         // from this point and up until main(). We request many frames to
         // make sure we reach main(), and then copy bottom portion of them.
-#if !defined(OS_NACL)  // We don't build base/debug/stack_trace.cc for NaCl.
-#if HAVE_TRACE_STACK_FRAME_POINTERS
-      const void* frames[128];
-      static_assert(arraysize(frames) >= Backtrace::kMaxFrameCount,
-                    "not requesting enough frames to fill Backtrace");
-      size_t frame_count = debug::TraceStackFramePointers(
-          frames, arraysize(frames),
-          1 /* exclude this function from the trace */);
-#else   // HAVE_TRACE_STACK_FRAME_POINTERS
-      // Fall-back to capturing the stack with base::debug::StackTrace,
-      // which is likely slower, but more reliable.
-      base::debug::StackTrace stack_trace(Backtrace::kMaxFrameCount);
-      size_t frame_count = 0u;
-      const void* const* frames = stack_trace.Addresses(&frame_count);
-#endif  // HAVE_TRACE_STACK_FRAME_POINTERS
+        const void* frames[128];
+        static_assert(arraysize(frames) >= Backtrace::kMaxFrameCount,
+                      "not requesting enough frames to fill Backtrace");
+#if HAVE_TRACE_STACK_FRAME_POINTERS && !defined(OS_NACL)
+        size_t frame_count = debug::TraceStackFramePointers(
+            frames,
+            arraysize(frames),
+            1 /* exclude this function from the trace */ );
+#else
+        size_t frame_count = 0;
+        NOTREACHED();
+#endif
 
-      // Copy frames backwards
-      size_t backtrace_capacity = backtrace_end - backtrace;
-      int32_t top_frame_index = (backtrace_capacity >= frame_count)
-                                    ? 0
-                                    : frame_count - backtrace_capacity;
-      for (int32_t i = frame_count - 1; i >= top_frame_index; --i) {
-        const void* frame = frames[i];
-        *backtrace++ = StackFrame::FromProgramCounter(frame);
+        // Copy frames backwards
+        size_t backtrace_capacity = backtrace_end - backtrace;
+        int32_t top_frame_index = (backtrace_capacity >= frame_count)
+                                      ? 0
+                                      : frame_count - backtrace_capacity;
+        for (int32_t i = frame_count - 1; i >= top_frame_index; --i) {
+          const void* frame = frames[i];
+          *backtrace++ = StackFrame::FromProgramCounter(frame);
+        }
+        break;
       }
-#endif  // !defined(OS_NACL)
-      break;
-    }
   }
 
   ctx->backtrace.frame_count = backtrace - std::begin(ctx->backtrace.frames);
 
   // TODO(ssid): Fix crbug.com/594803 to add file name as 3rd dimension
   // (component name) in the heap profiler and not piggy back on the type name.
   if (!task_contexts_.empty()) {
     ctx->type_name = task_contexts_.back();
   } else if (!pseudo_stack_.empty()) {
     // If task context was unavailable, then the category names are taken from
     // trace events.
     ctx->type_name = pseudo_stack_.back().trace_event_category;
   } else {
     ctx->type_name = nullptr;
   }
 
   return true;
 }
 
 }  // namespace trace_event
 }  // namespace base