Add an instancing perf test.

BUG=526217
BUG=angleproject:1164

Change-Id: Ia353a3b2fa0ab0e8b7fd15d72bb63e5ecb7833b1
Reviewed-on: https://chromium-review.googlesource.com/301469
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tryjob-Request: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>

samples/sample_util/SampleApplication.cpp

@@ -6,6 +6,7 @@
 
 #include "SampleApplication.h"
 #include "EGLWindow.h"
+#include "random_utils.h"
 
 SampleApplication::SampleApplication(const std::string &name,
                                      size_t width,
@@ -29,6 +30,8 @@ SampleApplication::SampleApplication(const std::string &name,
 
     // Disable vsync
     mEGLWindow->setSwapInterval(0);
+
+    angle::RandomInitFromTime();
 }
 
 SampleApplication::~SampleApplication()