Add a LocationUtils class to give all Chromium Android code access to location helpers.

components/location/android/java/src/org/chromium/components/location/LocationUtils.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.components.location;
+
+import android.Manifest;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import android.os.Process;
+import android.provider.Settings;
+import android.text.TextUtils;
+
+import org.chromium.base.ThreadUtils;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.base.annotations.SuppressFBWarnings;
+
+/**
+ * Provides methods for querying Chrome's ability to use Android's location services.
+ *
+ * This class should be used only on the UI thread.
+ */
+public class LocationUtils {
+    // Used to construct sInstance if that's null.
+    private static Factory sFactory;
+
+    private static LocationUtils sInstance;
+
+    protected LocationUtils() {}
+
+    /**
+     * Returns the singleton instance of LocationSettings, creating it if needed.
+     */
+    @SuppressFBWarnings("LI_LAZY_INIT_STATIC")
+    public static LocationUtils getInstance() {
+        ThreadUtils.assertOnUiThread();
+        if (sInstance == null) {
+            if (sFactory == null) {
+                sInstance = new LocationUtils();
+            } else {
+                sInstance = sFactory.create();
+            }
+        }
+        return sInstance;
+    }
+
+    private boolean hasPermission(Context context, String name) {
+        return context.checkPermission(name, Process.myPid(), Process.myUid())
+                == PackageManager.PERMISSION_GRANTED;
+    }
+
+    /**
+     * Returns true if Chromium has permission to access location.
+     *
+     * Check both chromeHasLocationPermission() and isSystemLocationSettingEnabled() to determine if

[Ted C, 2016/06/13 19:56:21]

looks like this comment predates the rename to chromium

[Jeffrey Yasskin, 2016/06/16 16:02:33]

Done.

+     * Chromium's location requests will return results.
+     */
+    public boolean chromiumHasLocationPermission(Context context) {

[Ted C, 2016/06/13 19:56:21]

personally, I would call this hasLocationAndroidPermission or
hasAndroidLocationPermission.  The chromium leading bit doesn't really help
differentiate anything in my opinion.

[Finnur, 2016/06/16 13:44:44]

FWIW: I'm also uncomfortable with the chromium prefix.

[Jeffrey Yasskin, 2016/06/16 16:02:33]

I was trying to distinguish this from some website having permission, but
omitting it works for me.

+        return hasPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION)
+                || hasPermission(context, Manifest.permission.ACCESS_FINE_LOCATION);
+    }
+
+    /**
+     * Returns whether location services are enabled system-wide, i.e. whether any application is
+     * able to access location.
+     */
+    public boolean isSystemLocationSettingEnabled(Context context) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+            return Settings.Secure.getInt(context.getContentResolver(),
+                           Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_OFF)
+                    != Settings.Secure.LOCATION_MODE_OFF;
+        } else {
+            return !TextUtils.isEmpty(Settings.Secure.getString(
+                    context.getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED));
+        }
+    }
+
+    /**
+     * Returns an intent to launch Android Location Settings.
+     */
+    public Intent getSystemLocationSettingsIntent() {
+        Intent i = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
+        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        return i;
+    }
+
+    /** Instantiate this to explain how to create a LocationUtils instance in

[Ted C, 2016/06/13 19:56:21]

move this down a line to avoid the off by one indenting weirdness

[Jeffrey Yasskin, 2016/06/16 16:02:33]

Done.

+     * LocationUtils.getInstance().
+     */
+    public interface Factory { public LocationUtils create(); }
+
+    /**
+     * Call this to use a different subclass of LocationUtils throughout the program.
+     * This can be used by embedders in addition to tests.
+     */
+    @VisibleForTesting
+    public static void setFactory(Factory factory) {
+        sFactory = factory;
+        sInstance = null;
+    }
+}