ImageCapture: fix using invalidated iterator after removing entry from |photo_request_queue_|

content/browser/renderer_host/media/video_capture_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/media/video_capture_manager.h"
 
 #include <algorithm>
 #include <set>
 #include <utility>
 
@@ skipping 502 matching lines @@
   }
   base::PostTaskAndReplyWithResult(
       device_task_runner_.get(), FROM_HERE, start_capture_function,
       base::Bind(&VideoCaptureManager::OnDeviceStarted, this,
                  request->serial_id()));
 }
 
 void VideoCaptureManager::OnDeviceStarted(
     int serial_id,
     std::unique_ptr<VideoCaptureDevice> device) {
+  DVLOG(3) << __func__;
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   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.
     // The device is no longer wanted. Stop the device again.
     DVLOG(3) << "OnDeviceStarted but start request have been aborted.";
     media::VideoCaptureDevice* device_ptr = device.get();
     base::Closure closure =
         base::Bind(&VideoCaptureManager::DoStopDeviceOnDeviceThread, this,
                    base::Passed(&device));
     if (device_ptr && !device_task_runner_->PostTask(FROM_HERE, closure)) {
       // PostTask failed. The device must be stopped anyway.
       device_ptr->StopAndDeAllocate();
     }
   } else {
     DeviceEntry* const entry = GetDeviceEntryBySerialId(serial_id);
     DCHECK(entry);
     DCHECK(!entry->video_capture_device());
     entry->SetVideoCaptureDevice(std::move(device));
 
     if (entry->stream_type == MEDIA_DESKTOP_VIDEO_CAPTURE) {
       const media::VideoCaptureSessionId session_id =
           device_start_queue_.front().session_id();
       DCHECK(session_id != kFakeSessionId);
       MaybePostDesktopCaptureWindowId(session_id);
     }
 
-    auto request = photo_request_queue_.begin();
-    while(request != photo_request_queue_.end()) {
+    auto it = photo_request_queue_.begin();
+    while (it != photo_request_queue_.end()) {
+      auto request = it++;
       DeviceEntry* maybe_entry = GetDeviceEntryBySessionId(request->first);
       if (maybe_entry && maybe_entry->video_capture_device()) {
         request->second.Run(maybe_entry->video_capture_device());
         photo_request_queue_.erase(request);
       }
-      ++request;
     }
   }
 
   device_start_queue_.pop_front();
   HandleQueuedStartRequest();
 }
 
 std::unique_ptr<media::VideoCaptureDevice>
 VideoCaptureManager::DoStartDeviceCaptureOnDeviceThread(
     const VideoCaptureDeviceDescriptor& descriptor,
@@ skipping 715 matching lines @@
     if (!device_in_queue) {
       // Session ID is only valid for Screen capture. So we can fake it to
       // resume video capture devices here.
       QueueStartDevice(kFakeSessionId, entry.get(), entry->parameters);
     }
   }
 }
 #endif  // defined(OS_ANDROID)
 
 }  // namespace content