Fix Android strict-mode violation in GeoLocation info bar.

chrome/browser/geolocation/chrome_geolocation_permission_context_android.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/geolocation/chrome_geolocation_permission_context_android.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/android/google_location_settings_helper.h"
+#include "chrome/browser/content_settings/permission_request_id.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 
 ChromeGeolocationPermissionContextAndroid::
     ChromeGeolocationPermissionContextAndroid(Profile* profile)
     : ChromeGeolocationPermissionContext(profile),
       google_location_settings_helper_(
           GoogleLocationSettingsHelper::Create()) {
 }
 
 ChromeGeolocationPermissionContextAndroid::
     ~ChromeGeolocationPermissionContextAndroid() {
 }
 
+void ChromeGeolocationPermissionContextAndroid::CallSuperDecidePermission(
+    const PermissionRequestID& id,
+    const GURL& requesting_frame,
+    const GURL& embedder,
+    base::Callback<void(bool)> callback) {
+  // Super class implementation expects everything in UI thread instead.
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  ChromeGeolocationPermissionContext::DecidePermission(
+      id, requesting_frame, embedder, callback);
+}
+
+void ChromeGeolocationPermissionContextAndroid::CheckMasterLocation(
+    const PermissionRequestID& id,
+    const GURL& requesting_frame,
+    const GURL& embedder,
+    base::Callback<void(bool)> callback) {
+  // Check to see if the feature in its entirety has been disabled.
+  // This must happen before other services (e.g. tabs, extensions)
+  // get an opportunity to allow the geolocation request.
+  bool enabled =
+      google_location_settings_helper_->IsMasterLocationSettingEnabled();
+
+  // Regardless of what the master setting is, we still need to
+  // go back to the UI thread for the rest of the bookkeeping.
+  if (enabled) {
+    content::BrowserThread::PostTask(
+        content::BrowserThread::UI, FROM_HERE,
+        base::Bind(
+            &ChromeGeolocationPermissionContextAndroid::
+                CallSuperDecidePermission,

[bulach, 2013/09/04 18:48:53]

is it possible to bind to DecidePermission directly?

[acleung1, 2013/09/05 21:50:16]

Yeah. I was struggling with this and couldn't find a good solution.

Binding DecidePermission will send it through the virtual dispatcher, calling
the child implementation again and creating a infinite loop.

I am happy to take any suggestions to avoid this.

+            base::Unretained(this), id, requesting_frame, embedder, callback));
+  } else {
+    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+        base::Bind(&ChromeGeolocationPermissionContextAndroid::
+                PermissionDecided,
+            base::Unretained(this), id,
+            requesting_frame, embedder, callback, false)); }

[bulach, 2013/09/04 18:48:53]

nit: move } to the next line..

it maybe slightly more readable as:

base::Closure ui_closure;
if (enabled) {
  ui_closure = base::Bind(...);
} else {
  ui_closure = base::Bind(...);
}

// This method is executed from the BlockingPool, post the result
// back to the UI thread.
content::BrowserThread::PostTask(
    content::BrowserThread::UI, FROM_HERE, ui_closure);

[acleung1, 2013/09/05 21:50:16]

Done.

+}
+
 void ChromeGeolocationPermissionContextAndroid::DecidePermission(
     const PermissionRequestID& id,
     const GURL& requesting_frame,
     const GURL& embedder,
     base::Callback<void(bool)> callback) {
-  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-
-  // Check to see if the feature in its entirety has been disabled.
-  // This must happen before other services (e.g. tabs, extensions)
-  // get an opportunity to allow the geolocation request.
-  if (!google_location_settings_helper_->IsMasterLocationSettingEnabled()) {
-    PermissionDecided(id, requesting_frame, embedder, callback, false);
-    return;
-  }
-
-  ChromeGeolocationPermissionContext::DecidePermission(id, requesting_frame,
-                                                       embedder, callback);
+  // The super class implementation requires this to be in the
+  // UI thread. We would like the work done else where to avoid
+  // strict mode violations.

[bulach, 2013/09/04 18:48:53]

rather than "the super class implementation requires", probably simplest to:

// Called on the UI thread. However, do the work on a separate thread
// to avoid strict mode violation.
DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));

[acleung1, 2013/09/05 21:50:16]

Done.

+  content::BrowserThread::PostBlockingPoolTask(FROM_HERE,
+      base::Bind(
+          &ChromeGeolocationPermissionContextAndroid::CheckMasterLocation,
+   base::Unretained(this), id, requesting_frame, embedder, callback));

[bulach, 2013/09/04 18:48:53]

nit: indentation

[acleung1, 2013/09/05 21:50:16]

Done.

 }
 
 void ChromeGeolocationPermissionContextAndroid::PermissionDecided(
     const PermissionRequestID& id,
     const GURL& requesting_frame,
     const GURL& embedder,
     base::Callback<void(bool)> callback,
     bool allowed) {
-  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   // If Google Apps Location setting is turned off then we ignore
   // the 'allow' website setting for this site and instead show
   // the infobar to go back to the 'settings' to turn it back on.
   if (allowed &&
       !google_location_settings_helper_->IsGoogleAppsLocationSettingEnabled()) {
     QueueController()->CreateInfoBarRequest(id, requesting_frame, embedder,
                                             callback);
     return;
   }
 
   ChromeGeolocationPermissionContext::PermissionDecided(
       id, requesting_frame, embedder, callback, allowed);
 }