Disable VR on standalone headsets

Currently we've got some bugs that can lead to crashes on standalone
VR headsets (https://vr.google.com/daydream/standalonevr/), so we
should detect devices that boot into VR, and disable VR there.

This will make sure we just use the fallback 2D-in-VR path that is
supposed to work for all apps :)

This also fixes a bug in scheduling rAF when presentation is rejected
that lead to the rAF loop doubling up every time presentation was
rejected.

Bug: 791090
Change-Id: I7511299935486dd018b558f3489ddd00f314ba8e
Reviewed-on: https://chromium-review.googlesource.com/809194
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521879}

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

@@ -63,4 +63,10 @@ public interface VrDaydreamApi {
      * Launch the stereoscopic, 3D VR launcher homescreen.
      */
     boolean launchVrHomescreen();
+
+    /**
+     * @return Whether this device boots directly into VR mode. May be used to detect standalone VR
+     * devices.
+     */
+    boolean bootsToVr();
 }

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

@@ -14,8 +14,10 @@ import android.os.StrictMode;
 import com.google.vr.ndk.base.DaydreamApi;
 import com.google.vr.ndk.base.GvrApi;
 
+import org.chromium.base.Log;
 import org.chromium.ui.base.WindowAndroid;
 
+import java.lang.reflect.Method;
 
 /**
  * A wrapper for DaydreamApi. Note that we have to recreate the DaydreamApi instance each time we
@@ -24,6 +26,10 @@ import org.chromium.ui.base.WindowAndroid;
 public class VrDaydreamApiImpl implements VrDaydreamApi {
     private final Context mContext;
 
+    private Boolean mBootsToVr = null;
+
+    public static final String VR_BOOT_SYSTEM_PROPERTY = "ro.boot.vr";
+
     public VrDaydreamApiImpl(Context context) {
         mContext = context;
     }
@@ -112,4 +118,28 @@ public class VrDaydreamApiImpl implements VrDaydreamApi {
         daydreamApi.close();
         return true;
     }
+
+    @Override
+    public boolean bootsToVr() {
+        if (mBootsToVr == null) {
+            // TODO(mthiesse): Replace this with a Daydream API call when supported.
+            // Note that System.GetProperty is unable to read system ro properties, so we have to
+            // resort to reflection as seen below. This method of reading system properties has been
+            // available since API level 1.
+            mBootsToVr = getIntSystemProperty(VR_BOOT_SYSTEM_PROPERTY, 0) == 1;
+        }
+        return mBootsToVr;
+    }
+
+    private int getIntSystemProperty(String key, int defaultValue) {
+        try {
+            final Class<?> systemProperties = Class.forName("android.os.SystemProperties");
+            final Method getInt = systemProperties.getMethod("getInt", String.class, int.class);
+            return (Integer) getInt.invoke(null, key, defaultValue);
+        } catch (Exception e) {
+            Log.e("Exception while getting system property %s. Using default %s.", key,
+                    defaultValue, e);
+            return defaultValue;
+        }
+    }
 }

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

@@ -318,7 +318,9 @@ public class VrShellDelegate
      */
     public static int getVrSupportLevel(VrDaydreamApi daydreamApi,
             VrCoreVersionChecker versionChecker, Tab tabToShowInfobarIn) {
-        if (versionChecker == null || daydreamApi == null
+        // TODO(mthiesse, crbug.com/791090): Re-enable VR mode for devices that boot to VR once we
+        // support those devices.
+        if (versionChecker == null || daydreamApi == null || daydreamApi.bootsToVr()
                 || !isVrCoreCompatible(versionChecker, tabToShowInfobarIn)) {
             return VR_NOT_AVAILABLE;
         }

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockVrDaydreamApi.java

@@ -65,4 +65,9 @@ public class MockVrDaydreamApi implements VrDaydreamApi {
     public boolean getLaunchInVrCalled() {
         return mLaunchInVrCalled;
     }
+
+    @Override
+    public boolean bootsToVr() {
+        return false;
+    }
 }

third_party/WebKit/Source/modules/vr/VRDisplay.cpp

@@ -1035,9 +1035,11 @@ void VRDisplay::OnMagicWindowPose(device::mojom::blink::VRPosePtr pose) {
 
 void VRDisplay::OnPresentationProviderConnectionError() {
   vr_presentation_provider_.reset();
-  ForceExitPresent();
-  pending_vsync_ = false;
-  RequestVSync();
+  if (is_presenting_) {
+    ForceExitPresent();
+    pending_vsync_ = false;
+    RequestVSync();
+  }
 }
 
 ScriptedAnimationController& VRDisplay::EnsureScriptedAnimationController(