Fix off-by-one in fps_meter, fix unit test to catch this.

chrome/browser/android/vr_shell/fps_meter_unittest.cc

Index: chrome/browser/android/vr_shell/fps_meter_unittest.cc
diff --git a/chrome/browser/android/vr_shell/fps_meter_unittest.cc b/chrome/browser/android/vr_shell/fps_meter_unittest.cc
index f5a9c0695defb6f7d441859fc7a2dcee386be2a5..6335af86289f67b3ab7f32bb130dc5077f3f1e85 100644
--- a/chrome/browser/android/vr_shell/fps_meter_unittest.cc
+++ b/chrome/browser/android/vr_shell/fps_meter_unittest.cc
@@ -49,7 +49,7 @@ TEST(FPSMeter, AccurateFPSWithManyFrames) {
   EXPECT_FALSE(meter.CanComputeFPS());
   EXPECT_FLOAT_EQ(0.0, meter.GetFPS());
 
-  for (int i = 0; i < 5; ++i) {
+  for (size_t i = 0; i < 2 * meter.GetNumFrameTimes(); ++i) {
     now += frame_time;
     meter.AddFrame(now);
     EXPECT_TRUE(meter.CanComputeFPS());