Clean up StrictMode.allowThreadDiskReads calls.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrDaydreamApiImpl.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrDaydreamApiImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrDaydreamApiImpl.java
index e73a1f340cc6acc3ff6af94bdc92e8debfe43600..e356018d583039151129d2b45e12399a6e7fb295 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrDaydreamApiImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrDaydreamApiImpl.java
@@ -82,10 +82,9 @@ public class VrDaydreamApiImpl implements VrDaydreamApi {
     public Boolean isDaydreamCurrentViewer() {
         DaydreamApi daydreamApi = DaydreamApi.create(mContext);
         if (daydreamApi == null) return false;
-        StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();

[mthiesse, 2017/04/28 16:04:08]

I think we *do* need both reads and writes allowed here. getCurrentViewerType()
can end up reading cardboard device parameters, which will be read from Android
SharedPreferences, which can cause disk reads.

[mthiesse, 2017/04/28 16:04:58]

Whoops disregard me, I failed to read the CL description.

         // If this is the first time any app reads the daydream config file, daydream may create its
         // config directory... crbug.com/686104
-        StrictMode.allowThreadDiskWrites();
+        StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskWrites();
         int type = GvrApi.ViewerType.CARDBOARD;
         try {
             type = daydreamApi.getCurrentViewerType();