Revert of Stop using -Wno-sentinel with clang.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 4a18e4da41882f2f4a2142e74a04847c6183e7f9..177cc99cbd7b1613336b59084eb5a73e7729f194 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -2428,6 +2428,11 @@
           '<(DEPTH)/base/allocator/allocator.gyp:type_profiler',
         ],
       }],
+      ['OS=="linux" and clang==1 and host_arch=="ia32"', {
+        # TODO(dmikurube): Remove -Wno-sentinel when Clang/LLVM is fixed.
+        # See http://crbug.com/162818.
+        'cflags+': ['-Wno-sentinel'],
+      }],
       ['branding=="Chrome"', {
         'defines': ['GOOGLE_CHROME_BUILD'],
       }, {  # else: branding!="Chrome"