net: Add fuzzer for HostResolverImpl.

net/base/fuzzed_data_provider.h

Index: net/base/fuzzed_data_provider.h
diff --git a/net/base/fuzzed_data_provider.h b/net/base/fuzzed_data_provider.h
index 47a45061cdf248b9a2da0bd5e94fb1399f04ba6b..4aa13db6c20a75634e437fd6cb5cfb86fb18b0fe 100644
--- a/net/base/fuzzed_data_provider.h
+++ b/net/base/fuzzed_data_provider.h
@@ -33,24 +33,33 @@ class FuzzedDataProvider {
   // FuzzedDataProvider is destroyed.
   base::StringPiece ConsumeRemainingBytes();
 
-  // Returns an unsigned number in the range [min, max] by consuming bytes from
-  // the input data. The value might not be uniformly distributed in the given
-  // range. If there's no input data left, always returns |min|. |min| must be
-  // less than or equal to |max|.
-  uint32_t ConsumeValueInRange(uint32_t min, uint32_t max);
+  // Returns a number in the range [min, max] by consuming bytes from the input
+  // data. The value might not be uniformly distributed in the given range. If
+  // there's no input data left, always returns |min|. |min| must be less than
+  // or equal to |max|.
+  uint32_t ConsumeUint32InRange(uint32_t min, uint32_t max);
+  int ConsumeInt32InRange(int min, int max);
 
   // Returns a bool, or false when no data remains.
   bool ConsumeBool();
 
   // Returns a uint8_t from the input or 0 if nothing remains. This is
-  // equivalent to ConsumeValueInRange(0, 0xFF).
+  // equivalent to ConsumeUint32InRange(0, 0xFF).
   uint8_t ConsumeUint8();
 
   // Returns a uint16_t from the input. If fewer than 2 bytes of data remain
   // will fill the most significant bytes with 0. This is equivalent to
-  // ConsumeValueInRange(0, 0xFFFF).
+  // ConsumeUint32InRange(0, 0xFFFF).
   uint16_t ConsumeUint16();
 
+  // Returns a value from |array|, consuming as many bytes as needed to do so.
+  // |array| must be a fixed-size array. Equivalent to
+  // array[ConsumeUint32InRange(sizeof(array)-1)];
+  template <typename Type, size_t size>
+  Type PickValueInArray(Type (&array)[size]) {
+    return array[ConsumeUint32InRange(0, size - 1)];
+  }
+
   // Reports the remaining bytes available for fuzzed input.
   size_t remaining_bytes() { return remaining_data_.length(); }