initial import of Chrome's trace_event into skia framework

gyp/tests.gyp

 # GYP file to build unit tests.
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
     {
       'target_name': 'tests',
       'type': 'executable',
       'include_dirs' : [
@@ skipping 134 matching lines @@
         '../tests/StreamTest.cpp',
         '../tests/StringTest.cpp',
         '../tests/StrokeTest.cpp',
         '../tests/SurfaceTest.cpp',
         '../tests/TLSTest.cpp',
         '../tests/TSetTest.cpp',
         '../tests/Test.cpp',
         '../tests/Test.h',
         '../tests/TestSize.cpp',
         '../tests/TileGridTest.cpp',
+        '../tests/TracingTest.cpp',
         '../tests/ToUnicode.cpp',
         '../tests/Typeface.cpp',
         '../tests/UnicodeTest.cpp',
         '../tests/UnitTestTest.cpp',
         '../tests/UtilsTest.cpp',
         '../tests/WArrayTest.cpp',
         '../tests/WritePixelsTest.cpp',
         '../tests/Writer32Test.cpp',
         '../tests/XfermodeTest.cpp',
         '../tests/skia_test.cpp',
@@ skipping 14 matching lines @@
       'conditions': [
         [ 'skia_gpu == 1', {
           'include_dirs': [
             '../src/gpu',
           ],
         }],
       ],
     },
   ],
 }