Add a fuzzer for SfntlyWrapper::SubsetFont().

base/test/fuzzed_data_provider.cc

Index: base/test/fuzzed_data_provider.cc
diff --git a/base/test/fuzzed_data_provider.cc b/base/test/fuzzed_data_provider.cc
index 5ea5862052a7fed7034d4e367e4a24c35f13788b..f2d4e0a468512d363ab400399ad5dbf8e3a17cb6 100644
--- a/base/test/fuzzed_data_provider.cc
+++ b/base/test/fuzzed_data_provider.cc
@@ -34,7 +34,7 @@ uint32_t FuzzedDataProvider::ConsumeUint32InRange(uint32_t min, uint32_t max) {
   uint32_t offset = 0;
   uint32_t result = 0;
 
-  while ((range >> offset) > 0 && !remaining_data_.empty()) {
+  while (offset < 32 && (range >> offset) > 0 && !remaining_data_.empty()) {
     // Pull bytes off the end of the seed data. Experimentally, this seems to

[hal.canary, 2016/08/23 15:49:04]

does this effect anything else?

[Lei Zhang, 2016/08/23 18:05:50]

Hmm?

     // allow the fuzzer to more easily explore the input space. This makes
     // sense, since it works by modifying inputs that caused new code to run,