Revert of Removing #defines previously used for building without BoringSSL/OpenSSL.

webrtc/base/helpers.cc

Index: webrtc/base/helpers.cc
diff --git a/webrtc/base/helpers.cc b/webrtc/base/helpers.cc
index aa6a6aea187f3e8e4f33b9788315264514fe0d0b..a8389d462e9c08b8db56f130d59109fcb0ccf877 100644
--- a/webrtc/base/helpers.cc
+++ b/webrtc/base/helpers.cc
@@ -13,7 +13,18 @@
 #include <limits>
 #include <memory>
 
+#if defined(FEATURE_ENABLE_SSL)
+#include "webrtc/base/sslconfig.h"
+#if defined(SSL_USE_OPENSSL)
 #include <openssl/rand.h>
+#else
+#if defined(WEBRTC_WIN)
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <ntsecapi.h>
+#endif  // WEBRTC_WIN
+#endif  // else
+#endif  // FEATURE_ENABLED_SSL
 
 #include "webrtc/base/base64.h"
 #include "webrtc/base/basictypes.h"
@@ -34,6 +45,7 @@
   virtual bool Generate(void* buf, size_t len) = 0;
 };
 
+#if defined(SSL_USE_OPENSSL)
 // The OpenSSL RNG.
 class SecureRandomGenerator : public RandomGenerator {
  public:
@@ -44,6 +56,79 @@
     return (RAND_bytes(reinterpret_cast<unsigned char*>(buf), len) > 0);
   }
 };
+
+#else
+#if defined(WEBRTC_WIN)
+class SecureRandomGenerator : public RandomGenerator {
+ public:
+  SecureRandomGenerator() : advapi32_(NULL), rtl_gen_random_(NULL) {}
+  ~SecureRandomGenerator() {
+    FreeLibrary(advapi32_);
+  }
+
+  virtual bool Init(const void* seed, size_t seed_len) {
+    // We don't do any additional seeding on Win32, we just use the CryptoAPI
+    // RNG (which is exposed as a hidden function off of ADVAPI32 so that we
+    // don't need to drag in all of CryptoAPI)
+    if (rtl_gen_random_) {
+      return true;
+    }
+
+    advapi32_ = LoadLibrary(L"advapi32.dll");
+    if (!advapi32_) {
+      return false;
+    }
+
+    rtl_gen_random_ = reinterpret_cast<RtlGenRandomProc>(
+        GetProcAddress(advapi32_, "SystemFunction036"));
+    if (!rtl_gen_random_) {
+      FreeLibrary(advapi32_);
+      return false;
+    }
+
+    return true;
+  }
+  virtual bool Generate(void* buf, size_t len) {
+    if (!rtl_gen_random_ && !Init(NULL, 0)) {
+      return false;
+    }
+    return (rtl_gen_random_(buf, static_cast<int>(len)) != FALSE);
+  }
+
+ private:
+  typedef BOOL (WINAPI *RtlGenRandomProc)(PVOID, ULONG);
+  HINSTANCE advapi32_;
+  RtlGenRandomProc rtl_gen_random_;
+};
+
+#elif !defined(FEATURE_ENABLE_SSL)
+
+// No SSL implementation -- use rand()
+class SecureRandomGenerator : public RandomGenerator {
+ public:
+  virtual bool Init(const void* seed, size_t len) {
+    if (len >= 4) {
+      srand(*reinterpret_cast<const int*>(seed));
+    } else {
+      srand(*reinterpret_cast<const char*>(seed));
+    }
+    return true;
+  }
+  virtual bool Generate(void* buf, size_t len) {
+    char* bytes = reinterpret_cast<char*>(buf);
+    for (size_t i = 0; i < len; ++i) {
+      bytes[i] = static_cast<char>(rand());
+    }
+    return true;
+  }
+};
+
+#else
+
+#error No SSL implementation has been selected!
+
+#endif  // WEBRTC_WIN
+#endif
 
 // A test random generator, for predictable output.
 class TestRandomGenerator : public RandomGenerator {