arc: Avoid turning on BT discoverable mode.

Current ARC Bluetooth bridge assumes that setting of discoverable
timeout implies the adapter should go into discoverable mode.

This change tracks the discoverable timeout separately from the actual
transition to discoverable mode, and only puts the adapter into
discoverable mode when the scan mode is set to discoverable.

Bug: 945076
Test: OOBE flow on kevin
Change-Id: I5b154af261563bb4d241327c81bb9a819259dcce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1559992Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Commit-Queue: Josh Horwich <jhorwich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649262}

chrome/browser/chromeos/arc/bluetooth/arc_bluetooth_bridge.cc

@@ -1059,7 +1059,7 @@ void ArcBluetoothBridge::SetAdapterProperty(
   if (property->is_discovery_timeout()) {
     uint32_t discovery_timeout = property->get_discovery_timeout();
     if (discovery_timeout > 0) {
-      SetDiscoverable(true, discovery_timeout);
+      discoverable_off_timeout_ = discovery_timeout;
     } else {
       OnSetAdapterProperty(mojom::BluetoothStatus::PARM_INVALID,
                            std::move(property));
@@ -1075,14 +1075,14 @@ void ArcBluetoothBridge::SetAdapterProperty(
                    weak_factory_.GetWeakPtr(), mojom::BluetoothStatus::FAIL,
                    base::Passed(&property_clone)));
   } else if (property->is_adapter_scan_mode()) {
-    // Android will set adapter scan mode in these 3 situations.
-    // 1) Set to BT_SCAN_MODE_NONE just before turning BT off.
-    // 2) Set to BT_SCAN_MODE_CONNECTABLE just after turning on.
-    // 3) Set to BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE just before set the
-    //    discoverable timeout.
-    // Since turning BT off/on implied scan mode none/connectable and setting
-    // discovery timeout implied scan mode discoverable, we don't need to
-    // do anything here. We will just call success callback in this case.
+    // Only set the BT scan mode to discoverable if requested and Android has
+    // set a discovery timeout previously.
+    if (property->get_adapter_scan_mode() ==
+        mojom::BluetoothScanMode::CONNECTABLE_DISCOVERABLE) {
+      SetDiscoverable(discoverable_off_timeout_ > 0, discoverable_off_timeout_);
+    } else {
+      SetDiscoverable(/*discoverable=*/false, /*timeout=*/0);
+    }
     OnSetAdapterProperty(mojom::BluetoothStatus::SUCCESS, std::move(property));
   } else {
     // Android does not set any other property type.

chrome/browser/chromeos/arc/bluetooth/arc_bluetooth_bridge.h

@@ -544,6 +544,8 @@ class ArcBluetoothBridge
   base::OneShotTimer discovery_off_timer_;
   // Timer to turn adapter discoverable off.
   base::OneShotTimer discoverable_off_timer_;
+  // Adapter discoverable timeout value.
+  uint32_t discoverable_off_timeout_ = 0;
 
   // Queue to track the powered state changes initiated by Android.
   base::queue<AdapterPowerState> remote_power_changes_;