Update documentation of memory-infra to describe updates to heap profiling.

docs/memory-infra/heap_profiler.md

 # Heap Profiling with MemoryInfra
 
 As of Chrome 48, MemoryInfra supports heap profiling. The core principle is
 a solution that JustWorks™ on all platforms without patching or rebuilding,
 integrated with the chrome://tracing ecosystem.
 
 [TOC]
 
 ## How to Use
 
@@ skipping 20 matching lines @@
 
 [memory-infra]:    README.md
 [m-purple]:        https://storage.googleapis.com/chromium-docs.appspot.com/d7bdf4d16204c293688be2e5a0bcb2bf463dbbc3
 [cells-heap-dump]: https://storage.googleapis.com/chromium-docs.appspot.com/a24d80d6a08da088e2e9c8b2b64daa215be4dacb
 
 ### Native stack traces
 
 By default heap profiling collects pseudo allocation traces, which are based
 on trace events. I.e. frames in allocation traces correspond to trace events
 that were active at the time of allocations, and are not real function names.
-However, you can build a special Linux / Android build that will collect
-real C/C++ stack traces.
+It's also possible to use heap profiling with native, symbolized stack traces.
+
+#### Native stack traces (macOS/Windows)
+
+1. Navigate to chrome://flags, and set "enable-heap-profiling" to Enabled
+   (native mode).
+
+2. Use the [TraceOnTap][extension-link] extension to grab a trace.
+
+3. Run the following script to symbolize the trace.
+
+        third_party/catapult/tracing/bin/symbolize_trace <trace file>
+
+4. Load the trace file in `chrome://tracing`. Locate a purple ![M][m-purple]
+   dot, and continue from step *3* from the instructions above. Native stack
+   traces will be shown in the _Heap Details_ pane.
+
+[extension-link]: https://cs.chromium.org/chromium/src/third_party/catapult/experimental/trace_on_tap/?q=traceontap+package:%5Echromium$&dr=CSs
+
+#### Native stack traces (Android/Linux)
+
+On Linux / Android, you need to build Chromium with special flags to use native

[awong, 2017/06/22 21:25:48]

You don't need this on Linux... That just turns on the pseudo-backtrace stuff
with frame pointers AFAIK.

[erikchen, 2017/06/22 21:35:40]

ah, but we don't have symbolization for Linux...Updated documentation.

+heap profiling.
 
  1. Build with the following GN flags:
 
         Linux
 
         enable_profiling = true
 
 
         Android
 
@@ skipping 106 matching lines @@
 memory allocated by PartitionAlloc alone, the total renderer memory increase was
 around 72 MiB.)
 
 ![Diff of The Verge before and after loading ads][diff]
 
 [pseudo-stack]:            https://storage.googleapis.com/chromium-docs.appspot.com/058e50350836f55724e100d4dbbddf4b9803f550
 [break-down-by-backtrace]: https://storage.googleapis.com/chromium-docs.appspot.com/ec61c5f15705f5bcf3ca83a155ed647a0538bbe1
 [break-down-by-type]:      https://storage.googleapis.com/chromium-docs.appspot.com/2236e61021922c0813908c6745136953fa20a37b
 [type-then-backtrace]:     https://storage.googleapis.com/chromium-docs.appspot.com/c5367dde11476bdbf2d5a1c51674148915573d11
 [diff]:                    https://storage.googleapis.com/chromium-docs.appspot.com/802141906869cd533bb613da5f91bd0b071ceb24