Revert of Upstream string_util function.

ios/chrome/ios_chrome.gyp

Index: ios/chrome/ios_chrome.gyp
diff --git a/ios/chrome/ios_chrome.gyp b/ios/chrome/ios_chrome.gyp
index 3b0d999253079190009fe2b17a613f2df57395f7..b2029dc7a65e6e8c5b4ee1bff1f098bf32f77514 100644
--- a/ios/chrome/ios_chrome.gyp
+++ b/ios/chrome/ios_chrome.gyp
@@ -39,7 +39,6 @@
         '../provider/ios_provider_chrome.gyp:ios_provider_chrome_browser',
         '../web/ios_web.gyp:ios_web',
         'injected_js',
-        'ios_chrome_common',
         'ios_chrome_resources.gyp:ios_theme_resources_gen',
       ],
       'link_settings': {
@@ -200,26 +199,6 @@
       ],
     },
     {
-      'target_name': 'ios_chrome_common',
-      'type': 'static_library',
-      'include_dirs': [
-        '../..',
-      ],
-      'dependencies': [
-        '../../base/base.gyp:base',
-      ],
-      'link_settings': {
-        'libraries': [
-          '$(SDKROOT)/System/Library/Frameworks/CoreGraphics.framework',
-          '$(SDKROOT)/System/Library/Frameworks/Foundation.framework',
-        ],
-      },
-      'sources': [
-        'common/string_util.h',
-        'common/string_util.mm',
-      ]
-    },
-    {
       'target_name': 'injected_js',
       'type': 'none',
       'sources': [