Revert of Revert of Revert of Add record-as-much-as-possible mode for about://tracing.

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 114 matching lines @@
   'src/third_party/angle':
    Var('chromium_git') + '/angle/angle.git' + '@' +  Var('angle_revision'),
 
   'src/third_party/colorama/src':
    Var('chromium_git') + '/external/colorama.git' + '@' + '799604a1041e9b3bc5d2789ecbd7e8db2e18e6b8',
 
   'src/third_party/crashpad/crashpad':
    Var('chromium_git') + '/crashpad/crashpad.git' + '@' + '5d0a133ecd6625f30c6491d502f12f26a0bef32d',
 
   'src/third_party/trace-viewer':
-   Var('chromium_git') + '/external/trace-viewer.git' + '@' + '31e508019823eb4846821b61ad492e3ea7483d71',
+   Var('chromium_git') + '/external/trace-viewer.git' + '@' + 'ff20313e37892c3c7f20c88bb22ab6f6e65659ae',
 
   'src/third_party/WebKit':
    Var('chromium_git') + '/chromium/blink.git' + '@' +  Var('webkit_revision'),
 
   'src/third_party/icu':
    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '7c81740601355556e630da515b74d889ba2f8d08',
 
   'src/third_party/libexif/sources':
    Var('chromium_git') + '/chromium/deps/libexif/sources.git' + '@' + 'ed98343daabd7b4497f97fda972e132e6877c48a',
 
@@ skipping 645 matching lines @@
     # corresponding .py files have already been deleted.
     'name': 'remove_stale_pyc_files',
     'pattern': 'src/tools/.*\\.py',
     'action': [
         'python',
         'src/tools/remove_stale_pyc_files.py',
         'src/tools',
     ],
   },
 ]