Don't silently ignore RNG failures when creating strings / numbers.

webrtc/base/helpers.h

Index: webrtc/base/helpers.h
diff --git a/webrtc/base/helpers.h b/webrtc/base/helpers.h
index 0e7937362a334c7cc29bc9a3ff203c1f7fec647c..6356a85fa1e0303cbcf1736e735c498df8906272 100644
--- a/webrtc/base/helpers.h
+++ b/webrtc/base/helpers.h
@@ -25,7 +25,7 @@ bool InitRandom(const char* seed, size_t len);
 
 // Generates a (cryptographically) random string of the given length.
 // We generate base64 values so that they will be printable.
-// WARNING: could silently fail. Use the version below instead.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 std::string CreateRandomString(size_t length);
 
 // Generates a (cryptographically) random string of the given length.
@@ -40,20 +40,40 @@ bool CreateRandomString(size_t length, const std::string& table,
                         std::string* str);
 
 // Generates a (cryptographically) random UUID version 4 string.
+// WARNING: will abort() if the RNG fails! Use the version below instead.

[mattdr-at-webrtc.org, 2016/07/01 23:57:39]

Suggest removing these warnings. The RNG will almost never fail, and when it
does something is seriously wrong and the app is probably on its way out anyway.
It's probably not worth it for callers to even consider changing their code.

[joachim, 2016/07/02 00:12:01]

Done.

 std::string CreateRandomUuid();
 
+// Generates a (cryptographically) random UUID version 4 string.
+bool CreateRandomUuid(std::string* uuid);

[mattdr-at-webrtc.org, 2016/07/01 23:57:39]

Likewise, no need to increase the surface area by adding another verison of each
function. The extra complexity adds essentially no value.

[joachim, 2016/07/02 00:12:01]

Done.

+
 // Generates a random id.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 uint32_t CreateRandomId();
 
+// Generates a random id.
+bool CreateRandomId(uint32_t* id);
+
 // Generates a 64 bit random id.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 uint64_t CreateRandomId64();
 
+// Generates a 64 bit random id.
+bool CreateRandomId64(uint64_t* id);
+
 // Generates a random id > 0.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 uint32_t CreateRandomNonZeroId();
 
+// Generates a random id > 0.
+bool CreateRandomNonZeroId(uint32_t* id);
+
 // Generates a random double between 0.0 (inclusive) and 1.0 (exclusive).
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 double CreateRandomDouble();
 
+// Generates a random double between 0.0 (inclusive) and 1.0 (exclusive).
+bool CreateRandomDouble(double* value);
+
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_HELPERS_H_