Fix StrictMode violations in ChromeBackupWatcher

Fixes disk read violations in ChromeBackupWatcher.java by briefly
allowing disk reads when notifying the backup manager that data has
changed.

Bug: 1018401
Change-Id: I220f8f967844a9af847777975595d891fb1201d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1888744Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710824}

chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupWatcher.java

@@ -9,6 +9,7 @@ import android.content.Context;
 import android.content.SharedPreferences;
 
 import org.chromium.base.ContextUtils;
+import org.chromium.base.StrictModeContext;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
@@ -39,7 +40,9 @@ public class ChromeBackupWatcher {
         SharedPreferences sharedPrefs = ContextUtils.getAppSharedPreferences();
         // If we have never done a backup do one immediately.
         if (!sharedPrefs.getBoolean(FIRST_BACKUP_DONE, false)) {
-            mBackupManager.dataChanged();
+            try (StrictModeContext ignored = StrictModeContext.allowDiskReads()) {
+                mBackupManager.dataChanged();
+            }
             sharedPrefs.edit().putBoolean(FIRST_BACKUP_DONE, true).apply();
         }
         sharedPrefs.registerOnSharedPreferenceChangeListener(
@@ -61,6 +64,8 @@ public class ChromeBackupWatcher {
 
     @CalledByNative
     private void onBackupPrefsChanged() {
-        mBackupManager.dataChanged();
+        try (StrictModeContext ignored = StrictModeContext.allowDiskReads()) {
+            mBackupManager.dataChanged();
+        }
     }
 }