gyp rules for ubsan

gyp/common_conditions.gypi

 # conditions used in both common.gypi and skia.gyp in chromium
 #
 {
   'defines': [
     'SK_ALLOW_STATIC_GLOBAL_INITIALIZERS=<(skia_static_initializers)',
     'SK_SUPPORT_GPU=<(skia_gpu)',
     'SK_SUPPORT_OPENCL=<(skia_opencl)',
     'SK_FORCE_DISTANCEFIELD_FONTS=<(skia_force_distancefield_fonts)',
   ],
   'conditions' : [
@@ skipping 393 matching lines @@
               [ 'skia_sanitizer == "thread"', {
                 'defines': [ 'DYNAMIC_ANNOTATIONS_ENABLED=1' ],
                 'cflags': [ '-fPIC' ],
                 'target_conditions': [
                   [ '_type == "executable"', {
                     'cflags': [ '-fPIE' ],
                     'ldflags': [ '-pie' ],
                   }],
                 ],
               }],
+              [ 'skia_sanitizer == "undefined"', {
+                'cflags': [ '-fPIC' ],
+                'cflags_cc!': ['-fno-rtti'],
+                'target_conditions': [
+                  [ '_type == "executable"', {
+                    'cflags': [ '-fPIE' ],
+                    'ldflags': [ '-pie' ],
+                  }],
+                ],
+              }],
             ],
           }],
           [ 'skia_clang_build', {
             'cflags': [
               # Extra warnings we like but that only Clang knows about.
               '-Wstring-conversion',
             ],
           }],
           [ 'skia_keep_frame_pointer', {
             'cflags': [ '-fno-omit-frame-pointer' ],
@@ skipping 195 matching lines @@
       'defines': [
         'SK_USE_POSIX_THREADS',
       ],
     }],
   ], # end 'conditions'
   # The Xcode SYMROOT must be at the root. See build/common.gypi in chromium for more details
   'xcode_settings': {
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }