🌕 Update binary_size/README.txt to have GN args rather than GYP_DEFINES

tools/binary_size/README.txt

 ================================================================================
               __________  .__
               \______   \ |__|   ____   _____    _______   ___.__.
                |    |  _/ |  |  /    \  \__  \   \_  __ \ <   |  |
                |    |   \ |  | |   |  \  / __ \_  |  | \/  \___  |
                |______  / |__| |___|  / (____  /  |__|     / ____|
                       \/            \/       \/            \/
     _________ .__                        ___________                   .__
    /   _____/ |__| ________   ____       \__    ___/   ____     ____   |  |
    \_____  \  |  | \___   / _/ __ \        |    |     /  _ \   /  _ \  |  |
@@ skipping 41 matching lines @@
 Running the tool is fairly simple. For the sake of this example we will
 pretend that you are building the Content Shell APK for Android.
 
   1. Build your product as you normally would*, e.g.:
        ninja -C out/Release -j 100 content_shell_apk
 
      * For results that are as spatially accurate as possible, you should always
      build with a Release configuration so that the end product is as close to
      the real thing as possible. However, it can sometimes be useful to improve
      consistency and accuracy of symbol lookup even if it perturbs the overall
-     accuracy of the tool. Consider adding these defines (e.g., via GYP_DEFINES
-     or GN build arguments):
-       clang=1
+     accuracy of the tool. Consider adding these GN args:
+       is_clang = true
          Anecdotally produces more stable symbol names over time.
-       profiling=1
-         Anecdotally makes symbol lookup more accurate (note that profiling=1
+       enable_profiling = true
+         Anecdotally makes symbol lookup more accurate (note that it
          doesn't work with clang on ARM/Android builds, see
          https://crbug.com/417323 for more information.
-       profiling_full_stack_frames=1
-         With profiling=1, should further improve symbol lookup accuracy but
-         will completely disable inlining, further decreasing spatial accuracy.
+       enable_full_stack_frames_for_profiling = true
+         With enable_profiling, further improves symbol lookup accuracy but
+         will completely disable inlining, decreasing spatial accuracy.
 
   2. Run the tool specifying the library and the output report directory.
      This command will run the analysis on the Content Shell native library for
      Android, producing an HTML report in /tmp/report and saving the NM output
      (useful for re-running the tool or analyzing deltas between two builds)
      under /tmp/report/nm.out:
        tools/binary_size/run_binary_size_analysis.py \
-         --library out/Release/lib/libcontent_shell_content_view.so \
+         --library out/Release/lib.unstripped/libcontent_shell_content_view.so \
          --destdir /tmp/report
 
 Of course, there are additional options that you can see by running the tool
 with "--help".
 
 This whole process takes about an hour on a modern (circa 2014) machine. If you
 have LOTS of RAM, you can use the "--jobs" argument to add more addr2line
 workers; doing so will *greatly* reduce the processing time but will devour
 system memory. If you've got the horsepower, 10 workers can thrash through the
 binary in about 5 minutes at a cost of around 60 GB of RAM. The default number
@@ skipping 53 matching lines @@
 
 --------------------------------------------------------------------------------
 Feature Requests and Bug Reports
 --------------------------------------------------------------------------------
 Please file bugs and feature requests here, making sure to use the label
 "Tools-BinarySize":
   https://code.google.com/p/chromium/issues/entry?labels=Tools-BinarySize
 
 View all open issues here:
   https://code.google.com/p/chromium/issues/list?can=2&q=label:Tools-BinarySize