Reland: ImageCapture: Queue up requests while device not ready

content/browser/renderer_host/media/video_capture_manager.cc

Index: content/browser/renderer_host/media/video_capture_manager.cc
diff --git a/content/browser/renderer_host/media/video_capture_manager.cc b/content/browser/renderer_host/media/video_capture_manager.cc
index 96fc5a10b2edcf228aacc628c3cc887dcf7a4b3c..9c0f5fa3f9aa42b2859da2100074a423579a0e81 100644
--- a/content/browser/renderer_host/media/video_capture_manager.cc
+++ b/content/browser/renderer_host/media/video_capture_manager.cc
@@ -518,8 +518,8 @@ void VideoCaptureManager::OnDeviceStarted(
     int serial_id,
     std::unique_ptr<VideoCaptureDevice> device) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  DCHECK(serial_id == device_start_queue_.begin()->serial_id());
-  DVLOG(3) << "OnDeviceStarted";
+  DCHECK_EQ(serial_id, device_start_queue_.begin()->serial_id());
+  DVLOG(3) << __func__;
   if (device_start_queue_.front().abort_start()) {
     // |device| can be null if creation failed in
     // DoStartDeviceCaptureOnDeviceThread.
@@ -545,6 +545,15 @@ void VideoCaptureManager::OnDeviceStarted(
       DCHECK(session_id != kFakeSessionId);
       MaybePostDesktopCaptureWindowId(session_id);
     }
+
+    auto request = photo_request_queue_.begin();
+    while(request != photo_request_queue_.end()) {
+      if (GetDeviceEntryBySessionId(request->first)->video_capture_device()) {
+        request->second.Run(entry->video_capture_device());
+        photo_request_queue_.erase(request);
+      }
+      ++request;
+    }
   }
 
   device_start_queue_.pop_front();
@@ -863,15 +872,19 @@ void VideoCaptureManager::GetPhotoCapabilities(
     int session_id,
     VideoCaptureDevice::GetPhotoCapabilitiesCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  VideoCaptureDevice* device = GetVideoCaptureDeviceBySessionId(session_id);
-  if (!device)
+
+  const DeviceEntry* entry = GetDeviceEntryBySessionId(session_id);
+  if (!entry)
     return;
-  // Unretained(device) is safe to use here because |device| would be null if it
-  // was scheduled for shutdown and destruction, and because this task is
-  // guaranteed to run before the task that destroys the |device|.
-  device_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VideoCaptureDevice::GetPhotoCapabilities,
-                            base::Unretained(device), base::Passed(&callback)));
+  VideoCaptureDevice* device = entry->video_capture_device();
+  if (device) {
+    VideoCaptureManager::DoGetPhotoCapabilities(std::move(callback), device);
+    return;
+  }
+  // |entry| is known but |device| is nullptr, queue up a request for later.
+  photo_request_queue_.emplace_back(
+      session_id, base::Bind(&VideoCaptureManager::DoGetPhotoCapabilities, this,
+                             base::Passed(&callback)));
 }
 
 void VideoCaptureManager::SetPhotoOptions(
@@ -879,28 +892,39 @@ void VideoCaptureManager::SetPhotoOptions(
     media::mojom::PhotoSettingsPtr settings,
     VideoCaptureDevice::SetPhotoOptionsCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  VideoCaptureDevice* device = GetVideoCaptureDeviceBySessionId(session_id);
-  if (!device)
+
+  const DeviceEntry* entry = GetDeviceEntryBySessionId(session_id);
+  if (!entry)
     return;
-  device_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&VideoCaptureDevice::SetPhotoOptions, base::Unretained(device),
-                 base::Passed(&settings), base::Passed(&callback)));
+  VideoCaptureDevice* device = entry->video_capture_device();
+  if (device) {
+    VideoCaptureManager::DoSetPhotoOptions(std::move(callback),
+                                           std::move(settings), device);
+    return;
+  }
+  // |entry| is known but |device| is nullptr, queue up a request for later.
+  photo_request_queue_.emplace_back(
+      session_id, base::Bind(&VideoCaptureManager::DoSetPhotoOptions, this,
+                             base::Passed(&callback), base::Passed(&settings)));
 }
 
 void VideoCaptureManager::TakePhoto(
     int session_id,
     VideoCaptureDevice::TakePhotoCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  VideoCaptureDevice* device = GetVideoCaptureDeviceBySessionId(session_id);
-  if (!device)
+
+  const DeviceEntry* entry = GetDeviceEntryBySessionId(session_id);
+  if (!entry)
     return;
-  // Unretained(device) is safe to use here because |device| would be null if it
-  // was scheduled for shutdown and destruction, and because this task is
-  // guaranteed to run before the task that destroys the |device|.
-  device_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VideoCaptureDevice::TakePhoto,
-                            base::Unretained(device), base::Passed(&callback)));
+  VideoCaptureDevice* device = entry->video_capture_device();
+  if (device) {
+    VideoCaptureManager::DoTakePhoto(std::move(callback), device);
+    return;
+  }
+  // |entry| is known but |device| is nullptr, queue up a request for later.
+  photo_request_queue_.emplace_back(
+      session_id, base::Bind(&VideoCaptureManager::DoTakePhoto, this,
+                             base::Passed(&callback)));
 }
 
 void VideoCaptureManager::DoStopDeviceOnDeviceThread(
@@ -1025,16 +1049,15 @@ void VideoCaptureManager::DestroyDeviceEntryIfNoClients(DeviceEntry* entry) {
   }
 }
 
-media::VideoCaptureDevice*
-VideoCaptureManager::GetVideoCaptureDeviceBySessionId(int session_id) {
+VideoCaptureManager::DeviceEntry*
+VideoCaptureManager::GetDeviceEntryBySessionId(int session_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   SessionMap::const_iterator session_it = sessions_.find(session_id);
   if (session_it == sessions_.end())
     return nullptr;
 
-  DeviceEntry* const device_info =
-      GetDeviceEntryByTypeAndId(session_it->second.type, session_it->second.id);
-  return device_info ? device_info->video_capture_device() : nullptr;
+  return GetDeviceEntryByTypeAndId(session_it->second.type,
+                                   session_it->second.id);
 }
 
 VideoCaptureManager::DeviceEntry*
@@ -1125,6 +1148,41 @@ void VideoCaptureManager::SetDesktopCaptureWindowIdOnDeviceThread(
 #endif
 }
 
+void VideoCaptureManager::DoGetPhotoCapabilities(
+    VideoCaptureDevice::GetPhotoCapabilitiesCallback callback,
+    VideoCaptureDevice* device) {
+  // Unretained() is safe to use here because |device| would be null if it
+  // was scheduled for shutdown and destruction, and because this task is
+  // guaranteed to run before the task that destroys the |device|.
+  device_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&VideoCaptureDevice::GetPhotoCapabilities,
+                            base::Unretained(device), base::Passed(&callback)));
+}
+
+void VideoCaptureManager::DoSetPhotoOptions(
+    VideoCaptureDevice::SetPhotoOptionsCallback callback,
+    media::mojom::PhotoSettingsPtr settings,
+    VideoCaptureDevice* device) {
+  // Unretained() is safe to use here because |device| would be null if it
+  // was scheduled for shutdown and destruction, and because this task is
+  // guaranteed to run before the task that destroys the |device|.
+  device_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&VideoCaptureDevice::SetPhotoOptions, base::Unretained(device),
+                 base::Passed(&settings), base::Passed(&callback)));
+}
+
+void VideoCaptureManager::DoTakePhoto(
+    VideoCaptureDevice::TakePhotoCallback callback,
+    VideoCaptureDevice* device) {
+  // Unretained() is safe to use here because |device| would be null if it
+  // was scheduled for shutdown and destruction, and because this task is
+  // guaranteed to run before the task that destroys the |device|.
+  device_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&VideoCaptureDevice::TakePhoto,
+                            base::Unretained(device), base::Passed(&callback)));
+}
+
 #if defined(OS_MACOSX)
 void VideoCaptureManager::OnDeviceLayerInitialized(
     const base::Closure& and_then) {