[Chromecast][BLE] Add APIs to pause/restart BLE scan

Bug: internal b/135576340
Test: Build and run
Change-Id: Iae347132d9302488a832902f38b6be8a4168783e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1762286Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Tiansong Cui <tiansong@google.com>
Cr-Commit-Position: refs/heads/master@{#689669}

chromecast/device/bluetooth/le/le_scan_manager_impl.cc

@@ -114,6 +114,28 @@ void LeScanManagerImpl::ClearScanResults() {
   addr_to_scan_results_.clear();
 }
 
+void LeScanManagerImpl::PauseScan() {
+  MAKE_SURE_IO_THREAD(PauseScan);
+  if (scan_handle_ids_.empty()) {
+    return;
+  }
+
+  if (!le_scanner_->StopScan()) {
+    LOG(ERROR) << "Failed to pause scanning";
+  }
+}
+
+void LeScanManagerImpl::RestartScan() {
+  MAKE_SURE_IO_THREAD(RestartScan);
+  if (scan_handle_ids_.empty()) {
+    return;
+  }
+
+  if (!le_scanner_->StartScan()) {
+    LOG(ERROR) << "Failed to restart scanning";
+  }
+}
+
 void LeScanManagerImpl::OnScanResult(
     const bluetooth_v2_shlib::LeScanner::ScanResult& scan_result_shlib) {
   LeScanResult scan_result;

chromecast/device/bluetooth/le/le_scan_manager_impl.h

@@ -43,6 +43,9 @@ class LeScanManagerImpl : public LeScanManager,
       base::Optional<ScanFilter> service_uuid = base::nullopt) override;
   void ClearScanResults() override;
 
+  void PauseScan();
+  void RestartScan();
+
  private:
   class ScanHandleImpl;
 

chromecast/device/bluetooth/le/le_scan_manager_impl_test.cc

@@ -97,6 +97,43 @@ TEST_F(LeScanManagerTest, TestEnableDisableScan) {
   task_environment_.RunUntilIdle();
 }
 
+TEST_F(LeScanManagerTest, TestPauseRestartScan) {
+  std::unique_ptr<LeScanManager::ScanHandle> scan_handle;
+
+  // Don't call StartScan or StopScan if there is no handle.
+  EXPECT_CALL(le_scanner_, StopScan()).Times(0);
+  le_scan_manager_.PauseScan();
+  EXPECT_CALL(le_scanner_, StartScan()).Times(0);
+  le_scan_manager_.RestartScan();
+  task_environment_.RunUntilIdle();
+
+  // Create a handle.
+  EXPECT_CALL(le_scanner_, StartScan()).WillOnce(Return(true));
+  EXPECT_CALL(mock_observer_, OnScanEnableChanged(true));
+  le_scan_manager_.RequestScan(base::BindOnce(
+      &CopyResult<std::unique_ptr<LeScanManager::ScanHandle>>, &scan_handle));
+  task_environment_.RunUntilIdle();
+  ASSERT_TRUE(scan_handle);
+
+  // Pause scan, we shouldn't declare scan is disabled.
+  EXPECT_CALL(mock_observer_, OnScanEnableChanged(_)).Times(0);
+  EXPECT_CALL(le_scanner_, StopScan()).WillOnce(Return(true));
+  le_scan_manager_.PauseScan();
+  task_environment_.RunUntilIdle();
+
+  // Restart scan.
+  EXPECT_CALL(mock_observer_, OnScanEnableChanged(_)).Times(0);
+  EXPECT_CALL(le_scanner_, StartScan()).WillOnce(Return(true));
+  le_scan_manager_.RestartScan();
+  task_environment_.RunUntilIdle();
+
+  // Delete the handle.
+  EXPECT_CALL(le_scanner_, StopScan()).WillOnce(Return(true));
+  EXPECT_CALL(mock_observer_, OnScanEnableChanged(false));
+  scan_handle.reset();
+  task_environment_.RunUntilIdle();
+}
+
 TEST_F(LeScanManagerTest, TestMultipleHandles) {
   static constexpr int kNumHandles = 20;