[Offline pages] Adding junit tests to OfflinePageUtils

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java

Index: chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java
index 3002a603014b0f8b8da30980bcade936c21973d5..1c0759ca5e0dcebba77083f71809587568282da5 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java
@@ -11,10 +11,12 @@ import android.os.BatteryManager;
 import android.os.Environment;
 
 import org.chromium.base.Log;
+import org.chromium.base.VisibleForTesting;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.snackbar.Snackbar;
 import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.snackbar.SnackbarManager.SnackbarController;
@@ -41,6 +43,15 @@ public class OfflinePageUtils {
 
     private static final long STORAGE_ALMOST_FULL_THRESHOLD_BYTES = 10L * (1 << 20); // 10M
 
+    private static OfflinePageUtils sInstance;
+
+    private static OfflinePageUtils getInstance() {
+        if (sInstance == null) {
+            sInstance = new OfflinePageUtils();
+        }
+        return sInstance;
+    }
+
     /**
      * Returns the number of free bytes on the storage.
      */
@@ -79,7 +90,7 @@ public class OfflinePageUtils {
         // Making sure tab is worth keeping.
         if (shouldSkipSavingTabOffline(tab)) return;
 
-        OfflinePageBridge offlinePageBridge = OfflinePageBridge.getForProfile(tab.getProfile());
+        OfflinePageBridge offlinePageBridge = getInstance().getOfflinePageBridge(tab.getProfile());
         if (offlinePageBridge == null) return;
 
         WebContents webContents = tab.getWebContents();
@@ -264,4 +275,13 @@ public class OfflinePageUtils {
         Log.d(TAG, "Battery Percentage is " + percentage);
         return percentage;
     }
+
+    protected OfflinePageBridge getOfflinePageBridge(Profile profile) {
+        return OfflinePageBridge.getForProfile(profile);
+    }
+
+    @VisibleForTesting
+    static void setInstanceForTesting(OfflinePageUtils instance) {
+        sInstance = instance;
+    }
 }