Intercept WebVR api calls and check for VrCore compatibility.

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.vr_shell;
 
+import android.os.Build;
+
 import com.google.vr.ndk.base.Version;
 import com.google.vr.vrcore.base.api.VrCoreNotAvailableException;
 import com.google.vr.vrcore.base.api.VrCoreUtils;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
 
+import org.chromium.chrome.browser.ChromeFeatureList;
+
 /**
  * Helper class to check if VrCore version is compatible with Chromium.
  */
 public class VrCoreVersionCheckerImpl implements VrCoreVersionChecker {
     private static final String TAG = "VrCoreVersionChecker";
 
+    private static final String MIN_SDK_VERSION_PARAM_NAME = "min_sdk_version";
+
     @Override
     public int getVrCoreCompatibility() {
+        // Supported Build version is determined by the webvr cardboard support feature.
+        // Default is KITKAT unless specified via server side finch config.
+        if (Build.VERSION.SDK_INT < ChromeFeatureList.getFieldTrialParamByFeatureAsInt(
+                                            ChromeFeatureList.WEBVR_CARDBOARD_SUPPORT,
+                                            MIN_SDK_VERSION_PARAM_NAME,
+                                            Build.VERSION_CODES.KITKAT)) {
+            return VrCoreVersionChecker.VR_NOT_SUPPORTED;
+        }
         try {
             String vrCoreSdkLibraryVersionString = VrCoreUtils.getVrCoreSdkLibraryVersion(
                     ContextUtils.getApplicationContext());
             Version vrCoreSdkLibraryVersion = Version.parse(vrCoreSdkLibraryVersionString);
             Version targetSdkLibraryVersion =
                     Version.parse(com.google.vr.ndk.base.BuildConstants.VERSION);
             if (!vrCoreSdkLibraryVersion.isAtLeast(targetSdkLibraryVersion)) {
                 return VrCoreVersionChecker.VR_OUT_OF_DATE;
             }
             return VrCoreVersionChecker.VR_READY;
         } catch (VrCoreNotAvailableException e) {
             Log.i(TAG, "Unable to find VrCore.");
             return VrCoreVersionChecker.VR_NOT_AVAILABLE;
         }
     }
 }