Have explicit send-all-mounts in VolumeMounter

This change add a method to request Chrome to send all existing mount
points. This method is called everytime vold is reseting.

Bug: 64500663
Change-Id: If10577a3d40ebd240a2ad242f703a28ecd3c363e
Reviewed-on: https://chromium-review.googlesource.com/938683
Commit-Queue: Risan <risan@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Luis Hector Chavez <lhchavez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539785}

components/arc/arc_bridge_service.h

@@ -81,6 +81,7 @@ class VoiceInteractionArcHomeHost;
 class VoiceInteractionArcHomeInstance;
 class VoiceInteractionFrameworkHost;
 class VoiceInteractionFrameworkInstance;
+class VolumeMounterHost;
 class VolumeMounterInstance;
 class WallpaperHost;
 class WallpaperInstance;
@@ -213,7 +214,8 @@ class ArcBridgeService {
   voice_interaction_framework() {
     return &voice_interaction_framework_;
   }
-  ConnectionHolder<mojom::VolumeMounterInstance>* volume_mounter() {
+  ConnectionHolder<mojom::VolumeMounterInstance, mojom::VolumeMounterHost>*
+  volume_mounter() {
     return &volume_mounter_;
   }
   ConnectionHolder<mojom::WallpaperInstance, mojom::WallpaperHost>*
@@ -274,7 +276,8 @@ class ArcBridgeService {
   ConnectionHolder<mojom::VoiceInteractionFrameworkInstance,
                    mojom::VoiceInteractionFrameworkHost>
       voice_interaction_framework_;
-  ConnectionHolder<mojom::VolumeMounterInstance> volume_mounter_;
+  ConnectionHolder<mojom::VolumeMounterInstance, mojom::VolumeMounterHost>
+      volume_mounter_;
   ConnectionHolder<mojom::WallpaperInstance, mojom::WallpaperHost> wallpaper_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcBridgeService);

components/arc/common/volume_mounter.mojom

@@ -33,13 +33,24 @@ struct MountPointInfo {
   string fs_uuid;
   // The file system label.
   string label;
-  // The device type that contains this mount point. If unknown, the event should be ignored.
+  // The device type that contains this mount point. If unknown, the event
+  // should be ignored.
   DeviceType device_type;
 };
 
+// Next Method ID: 1
+interface VolumeMounterHost {
+  // Requests all recorded MountPointInfos to be sent through a series of
+  // VolumeMounterInstance::OnMountEvent call.
+  [MinVersion=0] RequestAllMountPoints@1();
+};
+
 // Notifies Android about Mounting events.
+// Next Method ID: 2
 interface VolumeMounterInstance {
-  // @0 is reserved for Init().
+  // Establishes full-duplex communication with the host.
+  [MinVersion=1] Init@0(VolumeMounterHost host_ptr) => ();
+
   // Triggers a mount event in Android.
   OnMountEvent@1(MountPointInfo mount_point_info);
 };

components/arc/volume_mounter/arc_volume_mounter_bridge.cc

@@ -49,12 +49,14 @@ ArcVolumeMounterBridge::ArcVolumeMounterBridge(content::BrowserContext* context,
                                                ArcBridgeService* bridge_service)
     : arc_bridge_service_(bridge_service), weak_ptr_factory_(this) {
   arc_bridge_service_->volume_mounter()->AddObserver(this);
+  arc_bridge_service_->volume_mounter()->SetHost(this);
   DCHECK(DiskMountManager::GetInstance());
   DiskMountManager::GetInstance()->AddObserver(this);
 }
 
 ArcVolumeMounterBridge::~ArcVolumeMounterBridge() {
   DiskMountManager::GetInstance()->RemoveObserver(this);
+  arc_bridge_service_->volume_mounter()->SetHost(nullptr);
   arc_bridge_service_->volume_mounter()->RemoveObserver(this);
 }
 
@@ -147,4 +149,13 @@ void ArcVolumeMounterBridge::OnMountEvent(
       device_label, device_type));
 }
 
+void ArcVolumeMounterBridge::RequestAllMountPoints() {
+  // Deferring the SendAllMountEvents as a task to current thread to not
+  // block the mojo request since SendAllMountEvents might takes non trivial
+  // amount of time.
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::BindOnce(&ArcVolumeMounterBridge::SendAllMountEvents,
+                                weak_ptr_factory_.GetWeakPtr()));
+}
+
 }  // namespace arc

components/arc/volume_mounter/arc_volume_mounter_bridge.h

@@ -28,7 +28,8 @@ class ArcBridgeService;
 class ArcVolumeMounterBridge
     : public KeyedService,
       public chromeos::disks::DiskMountManager::Observer,
-      public ConnectionObserver<mojom::VolumeMounterInstance> {
+      public ConnectionObserver<mojom::VolumeMounterInstance>,
+      public mojom::VolumeMounterHost {
  public:
   // Returns singleton instance for the given BrowserContext,
   // or nullptr if the browser |context| is not allowed to use ARC.
@@ -62,6 +63,9 @@ class ArcVolumeMounterBridge
                      chromeos::RenameError error_code,
                      const std::string& device_path) override;
 
+  // mojom::VolumeMounterHost overrides:
+  void RequestAllMountPoints() override;
+
  private:
   void SendAllMountEvents();