Correctly handle enumerations for AudioManagers that report only the default audio output device.

BUG=578993

Review URL: https://codereview.chromium.org/1602083003

Cr-Commit-Position: refs/heads/master@{#370113}
(cherry picked from commit bbfc18f1577804ae0ee6f42d5866940116c97696)

Review URL: https://codereview.chromium.org/1607923002 .

Cr-Commit-Position: refs/branch-heads/2623@{#9}
Cr-Branched-From: 92d77538a86529ca35f9220bd3cd512cbea1f086-refs/heads/master@{#369907}

6 files changed, 148 insertions, 21 deletions

diff --git a/content/browser/renderer_host/media/audio_output_device_enumerator.cc b/content/browser/renderer_host/media/audio_output_device_enumerator.cc
index 70a4320..54c0531 100644
--- a/content/browser/renderer_host/media/audio_output_device_enumerator.cc
+++ b/content/browser/renderer_host/media/audio_output_device_enumerator.cc
@@ -23,16 +23,19 @@ AudioOutputDeviceEnumeration EnumerateDevicesOnDeviceThread(
   media::AudioDeviceNames device_names;
   audio_manager->GetAudioOutputDeviceNames(&device_names);
 
+  snapshot.has_actual_devices = !device_names.empty();
+
   // If no devices in enumeration, return a list with a default device
-  if (device_names.empty()) {
-    snapshot.push_back({media::AudioManagerBase::kDefaultDeviceId,
-                        media::AudioManager::GetDefaultDeviceName(),
-                        audio_manager->GetDefaultOutputStreamParameters()});
+  if (!snapshot.has_actual_devices) {
+    snapshot.devices.push_back(
+        {media::AudioManagerBase::kDefaultDeviceId,
+         media::AudioManager::GetDefaultDeviceName(),
+         audio_manager->GetDefaultOutputStreamParameters()});
     return snapshot;
   }
 
   for (const media::AudioDeviceName& name : device_names) {
-    snapshot.push_back(
+    snapshot.devices.push_back(
         {name.unique_id, name.device_name,
          name.unique_id == media::AudioManagerBase::kDefaultDeviceId
              ? audio_manager->GetDefaultOutputStreamParameters()
@@ -43,6 +46,16 @@ AudioOutputDeviceEnumeration EnumerateDevicesOnDeviceThread(
 
 }  // namespace
 
+AudioOutputDeviceEnumeration::AudioOutputDeviceEnumeration(
+    const std::vector<AudioOutputDeviceInfo>& devices,
+    bool has_actual_devices)
+    : devices(devices), has_actual_devices(has_actual_devices) {}
+
+AudioOutputDeviceEnumeration::AudioOutputDeviceEnumeration()
+    : has_actual_devices(false) {}
+
+AudioOutputDeviceEnumeration::~AudioOutputDeviceEnumeration() {}
+
 AudioOutputDeviceEnumerator::AudioOutputDeviceEnumerator(
     media::AudioManager* audio_manager,
     CachePolicy cache_policy)
diff --git a/content/browser/renderer_host/media/audio_output_device_enumerator.h b/content/browser/renderer_host/media/audio_output_device_enumerator.h
index 740e9c6..bf223a9 100644
--- a/content/browser/renderer_host/media/audio_output_device_enumerator.h
+++ b/content/browser/renderer_host/media/audio_output_device_enumerator.h
@@ -43,7 +43,19 @@ struct AudioOutputDeviceInfo {
   media::AudioParameters output_params;
 };
 
-typedef std::vector<AudioOutputDeviceInfo> AudioOutputDeviceEnumeration;
+// The result of an enumeration. It is used only in the browser side.
+struct AudioOutputDeviceEnumeration {
+ public:
+  AudioOutputDeviceEnumeration(
+      const std::vector<AudioOutputDeviceInfo>& devices,
+      bool has_actual_devices);
+  AudioOutputDeviceEnumeration();
+  ~AudioOutputDeviceEnumeration();
+
+  std::vector<AudioOutputDeviceInfo> devices;
+  bool has_actual_devices;
+};
+
 typedef base::Callback<void(const AudioOutputDeviceEnumeration&)>
     AudioOutputDeviceEnumerationCB;
 
@@ -59,11 +71,15 @@ class CONTENT_EXPORT AudioOutputDeviceEnumerator {
 
   // Does an enumeration and provides the results to the callback.
   // If there are no physical devices, the result contains a single entry with
-  // the default parameters provided by the underlying audio manager.
+  // the default parameters provided by the underlying audio manager and with
+  // the |has_actual_devices| field set to false.
   // The behavior with no physical devices is there to ease the transition
   // from the use of RenderThreadImpl::GetAudioHardwareConfig(), which always
   // provides default parameters, even if there are no devices.
   // See https://crbug.com/549125.
+  // Some audio managers always report a single device, regardless of the
+  // physical devices in the system. In this case the |has_actual_devices| field
+  // is set to true to differentiate from the case of no physical devices.
   void Enumerate(const AudioOutputDeviceEnumerationCB& callback);
 
   // Invalidates the current cache.
diff --git a/content/browser/renderer_host/media/audio_output_device_enumerator_unittest.cc b/content/browser/renderer_host/media/audio_output_device_enumerator_unittest.cc
index de1aa34..ac6140c 100644
--- a/content/browser/renderer_host/media/audio_output_device_enumerator_unittest.cc
+++ b/content/browser/renderer_host/media/audio_output_device_enumerator_unittest.cc
@@ -11,6 +11,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/thread_task_runner_handle.h"
 #include "content/browser/renderer_host/media/audio_output_device_enumerator.h"
 #include "content/public/test/test_browser_thread_bundle.h"
@@ -25,24 +26,62 @@ using testing::_;
 namespace content {
 
 namespace {
+
 class MockAudioManager : public media::FakeAudioManager {
  public:
-  MockAudioManager() : FakeAudioManager(&fake_audio_log_factory_) {}
+  MockAudioManager(size_t num_devices)
+      : FakeAudioManager(&fake_audio_log_factory_), num_devices_(num_devices) {}
+  MockAudioManager() : MockAudioManager(0) {}
   ~MockAudioManager() override {}
-  MOCK_METHOD1(GetAudioOutputDeviceNames, void(media::AudioDeviceNames*));
+
+  MOCK_METHOD1(MockGetAudioOutputDeviceNames, void(media::AudioDeviceNames*));
+
+  void GetAudioOutputDeviceNames(
+      media::AudioDeviceNames* device_names) override {
+    DCHECK(device_names->empty());
+    MockGetAudioOutputDeviceNames(device_names);
+    if (num_devices_ > 0) {
+      device_names->push_back(
+          media::AudioDeviceName(AudioManager::GetDefaultDeviceName(),
+                                 AudioManagerBase::kDefaultDeviceId));
+      for (size_t i = 0; i < num_devices_; i++) {
+        device_names->push_back(
+            media::AudioDeviceName("FakeDeviceName_" + base::IntToString(i),
+                                   "FakeDeviceId_" + base::IntToString(i)));
+      }
+    }
+  }
 
  private:
   media::FakeAudioLogFactory fake_audio_log_factory_;
+  size_t num_devices_;
   DISALLOW_COPY_AND_ASSIGN(MockAudioManager);
 };
+
+// Fake audio manager that exposes only the default device
+class OnlyDefaultDeviceAudioManager : public MockAudioManager {
+ public:
+  OnlyDefaultDeviceAudioManager() {}
+  ~OnlyDefaultDeviceAudioManager() override {}
+  void GetAudioOutputDeviceNames(
+      media::AudioDeviceNames* device_names) override {
+    DCHECK(device_names->empty());
+    MockGetAudioOutputDeviceNames(device_names);
+    device_names->push_front(
+        media::AudioDeviceName(AudioManager::GetDefaultDeviceName(),
+                               AudioManagerBase::kDefaultDeviceId));
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(OnlyDefaultDeviceAudioManager);
+};
+
 }  // namespace
 
 class AudioOutputDeviceEnumeratorTest : public ::testing::Test {
  public:
   AudioOutputDeviceEnumeratorTest()
-      : thread_bundle_(), task_runner_(base::ThreadTaskRunnerHandle::Get()) {
-    audio_manager_.reset(new MockAudioManager());
-  }
+      : thread_bundle_(), task_runner_(base::ThreadTaskRunnerHandle::Get()) {}
 
   ~AudioOutputDeviceEnumeratorTest() override {}
 
@@ -65,6 +104,14 @@ class AudioOutputDeviceEnumeratorTest : public ::testing::Test {
     }
   }
 
+  void EnumerateCountCallback(size_t num_entries_expected,
+                              bool actual_devices_expected,
+                              const AudioOutputDeviceEnumeration& result) {
+    EXPECT_EQ(actual_devices_expected, result.has_actual_devices);
+    EXPECT_EQ(num_entries_expected, result.devices.size());
+    task_runner_->PostTask(FROM_HERE, run_loop_.QuitClosure());
+  }
+
   void QuitCallback(const AudioOutputDeviceEnumeration& result) {
     MockCallback(result);
     task_runner_->PostTask(FROM_HERE, run_loop_.QuitClosure());
@@ -82,7 +129,8 @@ class AudioOutputDeviceEnumeratorTest : public ::testing::Test {
 
 TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateWithCache) {
   const int num_calls = 10;
-  EXPECT_CALL(*audio_manager_, GetAudioOutputDeviceNames(_)).Times(1);
+  audio_manager_.reset(new MockAudioManager());
+  EXPECT_CALL(*audio_manager_, MockGetAudioOutputDeviceNames(_)).Times(1);
   EXPECT_CALL(*this, MockCallback(_)).Times(num_calls);
   AudioOutputDeviceEnumerator enumerator(
       audio_manager_.get(),
@@ -95,7 +143,9 @@ TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateWithCache) {
 
 TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateWithNoCache) {
   const int num_calls = 10;
-  EXPECT_CALL(*audio_manager_, GetAudioOutputDeviceNames(_)).Times(num_calls);
+  audio_manager_.reset(new MockAudioManager());
+  EXPECT_CALL(*audio_manager_, MockGetAudioOutputDeviceNames(_))
+      .Times(num_calls);
   EXPECT_CALL(*this, MockCallback(_)).Times(num_calls);
   AudioOutputDeviceEnumerator enumerator(
       audio_manager_.get(),
@@ -106,4 +156,54 @@ TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateWithNoCache) {
   run_loop_.Run();
 }
 
+TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateNoDevices) {
+  audio_manager_.reset(new MockAudioManager());
+  EXPECT_CALL(*audio_manager_, MockGetAudioOutputDeviceNames(_));
+  AudioOutputDeviceEnumerator enumerator(
+      audio_manager_.get(),
+      AudioOutputDeviceEnumerator::CACHE_POLICY_NO_CACHING);
+  enumerator.Enumerate(
+      base::Bind(&AudioOutputDeviceEnumeratorTest::EnumerateCountCallback,
+                 base::Unretained(this), 1, false));
+  run_loop_.Run();
+}
+
+TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateOnlyDefaultDevice) {
+  audio_manager_.reset(new OnlyDefaultDeviceAudioManager());
+  EXPECT_CALL(*audio_manager_, MockGetAudioOutputDeviceNames(_));
+  AudioOutputDeviceEnumerator enumerator(
+      audio_manager_.get(),
+      AudioOutputDeviceEnumerator::CACHE_POLICY_NO_CACHING);
+  enumerator.Enumerate(
+      base::Bind(&AudioOutputDeviceEnumeratorTest::EnumerateCountCallback,
+                 base::Unretained(this), 1, true));
+  run_loop_.Run();
+}
+
+TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateOneDevice) {
+  size_t num_devices = 1;
+  audio_manager_.reset(new MockAudioManager(num_devices));
+  EXPECT_CALL(*audio_manager_, MockGetAudioOutputDeviceNames(_));
+  AudioOutputDeviceEnumerator enumerator(
+      audio_manager_.get(),
+      AudioOutputDeviceEnumerator::CACHE_POLICY_NO_CACHING);
+  enumerator.Enumerate(
+      base::Bind(&AudioOutputDeviceEnumeratorTest::EnumerateCountCallback,
+                 base::Unretained(this), num_devices + 1, true));
+  run_loop_.Run();
+}
+
+TEST_F(AudioOutputDeviceEnumeratorTest, EnumerateMultipleDevices) {
+  size_t num_devices = 5;
+  audio_manager_.reset(new MockAudioManager(num_devices));
+  EXPECT_CALL(*audio_manager_, MockGetAudioOutputDeviceNames(_));
+  AudioOutputDeviceEnumerator enumerator(
+      audio_manager_.get(),
+      AudioOutputDeviceEnumerator::CACHE_POLICY_NO_CACHING);
+  enumerator.Enumerate(
+      base::Bind(&AudioOutputDeviceEnumeratorTest::EnumerateCountCallback,
+                 base::Unretained(this), num_devices + 1, true));
+  run_loop_.Run();
+}
+
 }  // namespace content
diff --git a/content/browser/renderer_host/media/audio_renderer_host.cc b/content/browser/renderer_host/media/audio_renderer_host.cc
index 49e395b..d469d34 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.cc
+++ b/content/browser/renderer_host/media/audio_renderer_host.cc
@@ -840,9 +840,9 @@ void AudioRendererHost::TranslateDeviceID(
     const std::string& device_id,
     const GURL& security_origin,
     const OutputDeviceInfoCB& callback,
-    const AudioOutputDeviceEnumeration& device_infos) {
+    const AudioOutputDeviceEnumeration& enumeration) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  for (const AudioOutputDeviceInfo& device_info : device_infos) {
+  for (const AudioOutputDeviceInfo& device_info : enumeration.devices) {
     if (device_id.empty()) {
       if (device_info.unique_id == media::AudioManagerBase::kDefaultDeviceId) {
         callback.Run(true, device_info);
diff --git a/content/browser/renderer_host/media/audio_renderer_host.h b/content/browser/renderer_host/media/audio_renderer_host.h
index ce32fb1..e549df2 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.h
+++ b/content/browser/renderer_host/media/audio_renderer_host.h
@@ -231,7 +231,7 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   void TranslateDeviceID(const std::string& device_id,
                          const GURL& gurl_security_origin,
                          const OutputDeviceInfoCB& callback,
-                         const AudioOutputDeviceEnumeration& device_infos);
+                         const AudioOutputDeviceEnumeration& enumeration);
 
   // Helper method to check if the authorization procedure for stream
   // |stream_id| has started.
diff --git a/content/browser/renderer_host/media/media_stream_manager.cc b/content/browser/renderer_host/media/media_stream_manager.cc
index 49c828b..f602e8d 100644
--- a/content/browser/renderer_host/media/media_stream_manager.cc
+++ b/content/browser/renderer_host/media/media_stream_manager.cc
@@ -739,10 +739,8 @@ void MediaStreamManager::AudioOutputDevicesEnumerated(
   DVLOG(1) << "AudioOutputDevicesEnumerated()";
   StreamDeviceInfoArray device_infos;
 
-  // If the enumeration contains only one entry, it means there are no devices.
-  // The single entry contains default parameters from the audio manager.
-  if (device_enumeration.size() > 1) {
-    for (const auto& entry : device_enumeration) {
+  if (device_enumeration.has_actual_devices) {
+    for (const auto& entry : device_enumeration.devices) {
       StreamDeviceInfo device_info(MEDIA_DEVICE_AUDIO_OUTPUT, entry.device_name,
                                    entry.unique_id);
       device_infos.push_back(device_info);