Use VrClassesBuilder to reduce reflection usage

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/NonPresentingGvrContextImpl.java

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/NonPresentingGvrContextImpl.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/NonPresentingGvrContextImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/NonPresentingGvrContextImpl.java
index 876d3e1591c6a4cabcd693ede6919d2122bbc95f..b09e067ada393dab828ea061a50679dc212f41ab 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/NonPresentingGvrContextImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/NonPresentingGvrContextImpl.java
@@ -10,17 +10,14 @@ import android.os.StrictMode;
 import com.google.vr.ndk.base.GvrLayout;
 
 import org.chromium.base.Log;
-import org.chromium.base.annotations.UsedByReflection;
 
 /**
  * Creates an active GvrContext from a detached GvrLayout. This is used by magic window mode.
  */
-@UsedByReflection("VrShellDelegate.java")
 public class NonPresentingGvrContextImpl implements NonPresentingGvrContext {
     private static final String TAG = "NPGvrContextImpl";
     private GvrLayout mGvrLayout;
 
-    @UsedByReflection("VrShellDelegate.java")
     public NonPresentingGvrContextImpl(Activity activity) {
         mGvrLayout = new GvrLayout(activity);
     }