Add a mechanism to pause and resume geolocation requests.

content/browser/geolocation/geolocation_dispatcher_host.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 "content/browser/geolocation/geolocation_dispatcher_host.h"
 
 #include <map>
 #include <set>
 #include <utility>
 
@@ skipping 48 matching lines @@
   virtual ~GeolocationDispatcherHostImpl();
 
   void OnRequestPermission(int render_view_id,
                            int bridge_id,
                            const GURL& requesting_frame);
   void OnCancelPermissionRequest(int render_view_id,
                                  int bridge_id,
                                  const GURL& requesting_frame);
   void OnStartUpdating(int render_view_id,
                        const GURL& requesting_frame,
-      bool enable_high_accuracy);
+                       bool enable_high_accuracy);
   void OnStopUpdating(int render_view_id);
 
+
+  virtual void PauseOrResume(int render_view_id, bool should_pause) OVERRIDE;
+
   // Updates the |geolocation_provider_| with the currently required update
-  // options, based on |renderer_high_accuracy_|.
-  void RefreshHighAccuracy();
+  // options.
+  void RefreshGeolocationOptions();
 
   void OnLocationUpdate(const Geoposition& position);
 
   int render_process_id_;
   scoped_refptr<GeolocationPermissionContext> geolocation_permission_context_;
 
-  // Iterated when sending location updates to renderer processes. The fan out
-  // to individual bridge IDs happens renderer side, in order to minimize
-  // context switches.
+  struct RendererGeolocationOptions {
+    bool high_accuracy;
+    bool is_paused;
+  };
+
+  // Used to keep track of the renderers in this process that are using
+  // geolocation and the options associated with them. The map is iterated
+  // when a location update is available and the fan out to individual bridge
+  // IDs happens renderer side, in order to minimize context switches.
   // Only used on the IO thread.
-  std::set<int> geolocation_renderer_ids_;
-  // Maps renderer_id to whether high accuracy is requested for this particular
-  // bridge.
-  std::map<int, bool> renderer_high_accuracy_;
+  std::map<int, RendererGeolocationOptions> geolocation_renderers_;
+
+  // Used by Android WebView to support that case that a renderer is in the
+  // 'paused' state but not yet using geolocation. If the renderer does start
+  // using geolocation while paused, we move from this set into
+  // |geolocation_renderers_|. If the renderer doesn't end up wanting to use
+  // geolocation while 'paused' then we remove from this set. A renderer id
+  // can exist only in this set or |geolocation_renderers_|, never both.
+  std::set<int> pending_paused_geolocation_renderers_;
+
   // Only set whilst we are registered with the geolocation provider.
   GeolocationProviderImpl* geolocation_provider_;
 
   GeolocationProviderImpl::LocationUpdateCallback callback_;
 
   DISALLOW_COPY_AND_ASSIGN(GeolocationDispatcherHostImpl);
 };
 
 GeolocationDispatcherHostImpl::GeolocationDispatcherHostImpl(
     int render_process_id,
     GeolocationPermissionContext* geolocation_permission_context)
     : render_process_id_(render_process_id),
       geolocation_permission_context_(geolocation_permission_context),
       geolocation_provider_(NULL) {
   callback_ = base::Bind(
       &GeolocationDispatcherHostImpl::OnLocationUpdate, base::Unretained(this));
   // This is initialized by ResourceMessageFilter. Do not add any non-trivial
   // initialization here, defer to OnRegisterBridge which is triggered whenever
   // a javascript geolocation object is actually initialized.
 }
 
 GeolocationDispatcherHostImpl::~GeolocationDispatcherHostImpl() {
-  if (geolocation_provider_)
-    geolocation_provider_->RemoveLocationUpdateCallback(callback_);
+  if (geolocation_provider_) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        base::Bind(
+            base::IgnoreResult(
+                &GeolocationProvider::RemoveLocationUpdateCallback),
+            base::Unretained(geolocation_provider_), callback_));

[bulach, 2013/12/11 13:29:27]

I think GeolocationDispatcherHostImpl lives in the IO thread, right?
the problem with posting the task here is that GeolocationProvider would have
still have the callback pointing to |this| here... why is this post needed?

[benm (inactive), 2013/12/11 20:08:51]

hmm... I need to double check this again, IIRC calling it directly was causing
some tests to fail.

+  }
 }
 
 bool GeolocationDispatcherHostImpl::OnMessageReceived(
     const IPC::Message& msg, bool* msg_was_ok) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   *msg_was_ok = true;
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP_EX(GeolocationDispatcherHostImpl, msg, *msg_was_ok)
     IPC_MESSAGE_HANDLER(GeolocationHostMsg_CancelPermissionRequest,
                         OnCancelPermissionRequest)
     IPC_MESSAGE_HANDLER(GeolocationHostMsg_RequestPermission,
                         OnRequestPermission)
     IPC_MESSAGE_HANDLER(GeolocationHostMsg_StartUpdating, OnStartUpdating)
     IPC_MESSAGE_HANDLER(GeolocationHostMsg_StopUpdating, OnStopUpdating)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void GeolocationDispatcherHostImpl::OnLocationUpdate(
     const Geoposition& geoposition) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  for (std::set<int>::iterator it = geolocation_renderer_ids_.begin();
-       it != geolocation_renderer_ids_.end(); ++it) {
-    Send(new GeolocationMsg_PositionUpdated(*it, geoposition));
+  for (std::map<int, RendererGeolocationOptions>::iterator it =
+       geolocation_renderers_.begin();
+       it != geolocation_renderers_.end(); ++it) {
+    if (!(it->second.is_paused))
+      Send(new GeolocationMsg_PositionUpdated(it->first, geoposition));
   }
 }
 
 void GeolocationDispatcherHostImpl::OnRequestPermission(
     int render_view_id,
     int bridge_id,
     const GURL& requesting_frame) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
            << render_view_id << ":" << bridge_id;
@@ skipping 33 matching lines @@
     const GURL& requesting_frame,
     bool enable_high_accuracy) {
   // StartUpdating() can be invoked as a result of high-accuracy mode
   // being enabled / disabled. No need to record the dispatcher again.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
            << render_view_id;
   UMA_HISTOGRAM_BOOLEAN(
       "Geolocation.GeolocationDispatcherHostImpl.EnableHighAccuracy",
       enable_high_accuracy);
-  if (!geolocation_renderer_ids_.count(render_view_id))
-    geolocation_renderer_ids_.insert(render_view_id);
 
-  renderer_high_accuracy_[render_view_id] = enable_high_accuracy;
-  RefreshHighAccuracy();
+  std::map<int, RendererGeolocationOptions>::iterator it =
+            geolocation_renderers_.find(render_view_id);
+  if (it == geolocation_renderers_.end()) {
+    bool should_start_paused = false;
+    if (pending_paused_geolocation_renderers_.erase(render_view_id) == 1) {
+      should_start_paused = true;
+    }
+    RendererGeolocationOptions opts = {
+      enable_high_accuracy,
+      should_start_paused
+    };
+    geolocation_renderers_[render_view_id] = opts;
+  } else {
+    RendererGeolocationOptions* opts = &(it->second);
+      opts->high_accuracy = enable_high_accuracy;

[bulach, 2013/12/11 13:29:27]

nit: unindent, but tbh, perhaps just:

it->second.opts.high_accuracy = enable_high_accuracy;

[benm (inactive), 2013/12/11 20:08:51]

Done.

+  }
+  RefreshGeolocationOptions();
 }
 
 void GeolocationDispatcherHostImpl::OnStopUpdating(int render_view_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
            << render_view_id;
-  if (renderer_high_accuracy_.erase(render_view_id))
-    RefreshHighAccuracy();
-
-  DCHECK_EQ(1U, geolocation_renderer_ids_.count(render_view_id));
-  geolocation_renderer_ids_.erase(render_view_id);
+  DCHECK_EQ(1U, geolocation_renderers_.count(render_view_id));
+  geolocation_renderers_.erase(render_view_id);
+  RefreshGeolocationOptions();
 }
 
-void GeolocationDispatcherHostImpl::RefreshHighAccuracy() {
+void GeolocationDispatcherHostImpl::PauseOrResume(int render_view_id,
+                                                  bool should_pause) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  if (renderer_high_accuracy_.empty()) {
-    if (geolocation_provider_) {
-      geolocation_provider_->RemoveLocationUpdateCallback(callback_);
-      geolocation_provider_ = NULL;
+  std::map<int, RendererGeolocationOptions>::iterator it =
+      geolocation_renderers_.find(render_view_id);
+  if (it == geolocation_renderers_.end()) {
+    // This renderer is not using geolocation yet, but if it does before
+    // we get a call to resume, we should start it up in the paused state.
+    if (should_pause) {
+      pending_paused_geolocation_renderers_.insert(render_view_id);
+    } else {
+      pending_paused_geolocation_renderers_.erase(render_view_id);
     }
   } else {
+    RendererGeolocationOptions* opts = &(it->second);
+    if (opts->is_paused != should_pause)
+      opts->is_paused = should_pause;
+    RefreshGeolocationOptions();
+  }
+}
+
+void GeolocationDispatcherHostImpl::RefreshGeolocationOptions() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  bool needs_updates = false;
+  bool use_high_accuracy = false;
+  std::map<int, RendererGeolocationOptions>::const_iterator i =
+      geolocation_renderers_.begin();
+  for (; i != geolocation_renderers_.end(); ++i) {
+    needs_updates |= !(i->second.is_paused);
+    use_high_accuracy |= i->second.high_accuracy;
+    if (needs_updates && use_high_accuracy)
+      break;
+  }
+  if (needs_updates) {
     if (!geolocation_provider_)
       geolocation_provider_ = GeolocationProviderImpl::GetInstance();
     // Re-add to re-establish our options, in case they changed.
-    bool use_high_accuracy = false;
-    std::map<int, bool>::iterator i = renderer_high_accuracy_.begin();
-    for (; i != renderer_high_accuracy_.end(); ++i) {
-      if (i->second) {
-        use_high_accuracy = true;
-        break;
-      }
-    }
     geolocation_provider_->AddLocationUpdateCallback(
         callback_, use_high_accuracy);
+  } else {
+    if (geolocation_provider_)
+      geolocation_provider_->RemoveLocationUpdateCallback(callback_);
+    geolocation_provider_ = NULL;
   }
 }
+
 }  // namespace
 
 
 // GeolocationDispatcherHost --------------------------------------------------
 
 // static
 GeolocationDispatcherHost* GeolocationDispatcherHost::New(
     int render_process_id,
     GeolocationPermissionContext* geolocation_permission_context) {
   return new GeolocationDispatcherHostImpl(
       render_process_id,
       geolocation_permission_context);
 }
 
 GeolocationDispatcherHost::GeolocationDispatcherHost() {
 }
 
 GeolocationDispatcherHost::~GeolocationDispatcherHost() {
 }
 
 }  // namespace content