Add fuzzer to test Fuzz URLRequestDataJob

net/base/fuzzed_data_provider.cc

Index: net/base/fuzzed_data_provider.cc
diff --git a/net/base/fuzzed_data_provider.cc b/net/base/fuzzed_data_provider.cc
index 6278ff2ff9a1363aa2922763e5b485c8f59c2cfa..30f45f7e96a1d3b48c07dcc55c4ebf27f996dd97 100644
--- a/net/base/fuzzed_data_provider.cc
+++ b/net/base/fuzzed_data_provider.cc
@@ -38,7 +38,7 @@ uint32_t FuzzedDataProvider::ConsumeBits(size_t num_bits) {
       bits_to_add = num_bits;
     new_bits &= new_bits & ((1 << bits_to_add) - 1);
     out = (out << bits_to_add) | new_bits;
-    num_bits -= bits_to_add;
+    num_bits = num_bits > bits_to_add ? num_bits - bits_to_add : 0;
   }
 
   return out;