Update trace-viewer to r1534

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
 # where <gcliendir> is the absolute path to the directory containing the
 # .gclient file (the parent of 'src').
 #
@@ skipping 98 matching lines @@
   'src/testing/gmock':
    Var('chromium_git') + '/external/googlemock.git' + '@' + '896ba0e03f520fb9b6ed582bde2bd00847e3c3f2', # from svn revision 485
 
   '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/trace-viewer':
-   Var('chromium_git') + '/external/trace-viewer.git' + '@' + '172d4941a79a3354b918f85bc9a3ea9c134fc1ad', # from svn revision 1532
+   Var('chromium_git') + '/external/trace-viewer.git' + '@' + '56b74bad6d1485bb8e54ca0a9539da9842e695ca', # from svn revision 1534
 
   'src/third_party/WebKit':
    Var('chromium_git') + '/chromium/blink.git' + '@' +  Var('webkit_revision'),
 
   'src/third_party/WebKit/LayoutTests/w3c/web-platform-tests':
    Var('chromium_git') + '/external/w3c/web-platform-tests.git' + '@' + '3e0f28376857901b2d3eefda82a3b622bbcabd41',
 
   'src/third_party/WebKit/LayoutTests/w3c/csswg-test':
    Var('chromium_git') + '/external/w3c/csswg-test.git' + '@' + '0b12ea22689ee2179f3e9bff389db22f4efd6ed5',
 
@@ skipping 669 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',
     ],
   },
 ]