VR: Early return in VrMainActivity for non-Daydream ready devices

This CL also wraps the DaydreamApi.isInVrSession call with isDaydreamReadyDevice
to prevent a Daydream-side crash

Bug: 827174
Change-Id: I7207bae82818bc0a77bc66f5c45bb8401675796e
Reviewed-on: https://chromium-review.googlesource.com/986672Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Yash Malik <ymalik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547717}

chrome/android/java/src/org/chromium/chrome/browser/vr/VrMainActivity.java

@@ -39,6 +39,11 @@ public class VrMainActivity extends Activity {
         try {
             super.onCreate(savedInstanceState);
 
+            if (!VrShellDelegate.isDaydreamReadyDevice(this)) {
+                finish();
+                return;
+            }
+
             // If the launcher was launched from a 2D context (without calling
             // DaydreamApi#launchInVr), then we need to relaunch the launcher in VR to allow
             // downstream Activities to make assumptions about whether they're in VR or not, and

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

@@ -146,7 +146,9 @@ public class VrDaydreamApiImpl implements VrDaydreamApi {
 
     @Override
     public boolean isInVrSession() {
-        return DaydreamApi.isInVrSession(mContext);
+        // The call to isInVrSession crashes when called on a non-Daydream ready device, so we add
+        // the device check (b/77268533).
+        return isDaydreamReadyDevice() && DaydreamApi.isInVrSession(mContext);
     }
 
     @Override

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

@@ -784,6 +784,15 @@ public class VrShellDelegate
         return api.isInVrSession();
     }
 
+    public static boolean isDaydreamReadyDevice(Activity activty) {
+        if (sInstance != null) return sInstance.mVrDaydreamApi.isDaydreamReadyDevice();
+        VrClassesWrapper wrapper = getVrClassesWrapper();
+        if (wrapper == null) return false;
+        VrDaydreamApi api = wrapper.createVrDaydreamApi(activty);
+        if (api == null) return false;
+        return api.isDaydreamReadyDevice();
+    }
+
     // TODO(mthiesse): Should have package visibility only. We need to unify our vr and vr_shell
     // packages.
     public static boolean willChangeDensityInVr(ChromeActivity activity) {