Remove dependency from //mojo to //crypto

mojo/dart/embedder/test/validation_unittest.cc

Index: mojo/dart/embedder/test/validation_unittest.cc
diff --git a/mojo/dart/embedder/test/validation_unittest.cc b/mojo/dart/embedder/test/validation_unittest.cc
index bf5b87c929a6cd819c9d0a687cbbaeab8c76bc64..15132583bf1e501a345eeb8eb1a4314732f4a3e3 100644
--- a/mojo/dart/embedder/test/validation_unittest.cc
+++ b/mojo/dart/embedder/test/validation_unittest.cc
@@ -13,7 +13,7 @@
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
-#include "crypto/random.h"
+#include "base/rand_util.h"
 #include "mojo/dart/embedder/dart_controller.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -36,7 +36,7 @@ std::string GetPath() {
 }
 
 static bool generateEntropy(uint8_t* buffer, intptr_t length) {
-  crypto::RandBytes(reinterpret_cast<void*>(buffer), length);
+  base::RandBytes(reinterpret_cast<void*>(buffer), length);
   return true;
 }