Stubs for triggering the LSD in Clank

chrome/browser/android/location_settings.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_ANDROID_LOCATION_SETTINGS_H_
 #define CHROME_BROWSER_ANDROID_LOCATION_SETTINGS_H_
 
+#include "base/callback.h"
 #include "base/macros.h"
 
 namespace content {
 class WebContents;
 }
 
 // This class determines whether Chrome can access the device's location,
 // i.e. whether location is enabled system-wide on the device.
 class LocationSettings {
  public:
   virtual ~LocationSettings() {}
 
   // Returns true if:
   //  - Location is enabled system-wide (in Android settings)
   //  - The necessary location permission are granted to Chrome, or if Chrome
   //    still has the ability to request the permissions to be granted.
   virtual bool CanSitesRequestLocationPermission(
       content::WebContents* web_contents) = 0;
+
+  // Asynchronously checks if a prompt can be triggered to ask the user to turn

[benwells, 2017/02/28 06:51:38]

Is it necessary for this to be async? It makes the permission side a little
nastier if it is.

+  // on the system location setting on their device, and returns true iff a
+  // prompt can be triggered.
+  // In particular, returns false if the system location setting is already
+  // enabled or if some of the features required to trigger a system location
+  // setting prompt are not available.
+  virtual void CanPromptToEnableSystemLocationSetting(
+      const base::Callback<void(bool can_prompt)>& callback) = 0;
+
+  // An enum to describe the context in which a system location setting prompt
+  // is triggered to allow the prompt UI to be customized to the given context.
+  //
+  // Keep in sync with the PromptContext IntDef in
+  // https://cs.chromium.org/chromium/src/components/location/android/java/src/org/chromium/components/location/LocationUtils.java

[benwells, 2017/02/28 06:26:36]

Nit: you can refer to source files as //components/location/...etc. without the
bit https://cs.chromium.org... etc prefix.

+  enum PromptContext {

[benwells, 2017/02/28 07:03:26]

This (and PromptOutcome) are a bit vague - there might be other prompts at some
stage. Can we make the names more specific, e.g.
LocationSettingsDialogPromptContext?

+    // Prompt triggered in the context of a user gesture on a web page or on
+    // a preliminary domain or app permission prompt.
+    GESTURE = 1,

[benwells, 2017/02/28 06:26:36]

Nit: I think we should call this NON_SEARCH. We might one day relax or change
the gesture requirement.

+    // Prompt triggered in the context of a search.
+    SEARCH = 2,
+  };
+
+  // An enum to describe the outcome of a location setting prompt triggered by
+  // PromptToEnableSystemLocationSetting().
+  //
+  // Keep in sync with the PromptOutcome IntDef in
+  // https://cs.chromium.org/chromium/src/components/location/android/java/src/org/chromium/components/location/LocationUtils.java
+  enum PromptOutcome {
+    // The user accepted the prompt and the system location setting has been
+    // flipped to granted.
+    GRANTED = 1,
+
+    // The user rejected the prompt and the system location setting has not been
+    // flipped.
+    DENIED = 2,
+
+    // The prompt could not be triggered.
+    // When CanPromptToEnableSystemLocationSetting() returns true, this should
+    // only happen in exceptional circonstances, e.g.
+    // - In the case of a race condition where the system location setting is
+    // flipped elsewhere before the prompt could be triggered;
+    // - In the case where some of the features required to trigger a system
+    // location setting prompt became unavailable or unresponsive after the
+    // response from CanPromptToEnableSystemLocationSetting() was received.
+    NO_PROMPT = 3,
+  };
+
+  // Triggers a prompt to ask the user to turn on the system location setting on
+  // their device.
+  // The prompt will be triggered in the activity of the web contents.
+  virtual void PromptToEnableSystemLocationSetting(
+      const PromptContext prompt_context,
+      content::WebContents* web_contents,
+      const base::Callback<void(PromptOutcome prompt_outcome)>& callback) = 0;
 };
 
 #endif  // CHROME_BROWSER_ANDROID_LOCATION_SETTINGS_H_