Roll ICU 239289:258359 and add support for external ICU data tables

tools/gyp/v8.gyp

Index: tools/gyp/v8.gyp
diff --git a/tools/gyp/v8.gyp b/tools/gyp/v8.gyp
index 6f97defe04f5e2525846c7275ca952be90c1b3a4..be6faf4fb4c0ac3655e0760365a3ab2f64aa90b8 100644
--- a/tools/gyp/v8.gyp
+++ b/tools/gyp/v8.gyp
@@ -27,6 +27,7 @@
 
 {
   'variables': {
+    'icu_use_data_file_flag%': 0,
     'v8_code': 1,
     'v8_random_seed%': 314159265,
   },
@@ -1018,6 +1019,17 @@
             '../../src/default-platform.h',
           ],
         }],
+        ['icu_use_data_file_flag==1', {
+          'defines': ['ICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE'],
+        }, { # else icu_use_data_file_flag !=1
+          'conditions': [
+            ['OS=="win"', {
+              'defines': ['ICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_SHARED'],
+            }, {
+              'defines': ['ICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_STATIC'],
+            }],
+          ],
+        }],
       ],
     },
     {