Add missing checks for parameter validity in VideoCaptureHost.

Bug: 1133812
Change-Id: I32e8fafc3c4a190a5b1f6be905bf2f1f829b473f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2503556Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Mark Brand <markbrand@google.com>
Cr-Commit-Position: refs/heads/master@{#826248}

content/browser/renderer_host/media/video_capture_host.cc

@@ -191,6 +191,11 @@ void VideoCaptureHost::Start(
            << media::VideoCaptureFormat::ToString(params.requested_format);
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
+  if (!params.IsValid()) {
+    mojo::ReportBadMessage("Invalid video capture params.");
+    return;
+  }
+
   DCHECK(!base::Contains(device_id_to_observer_map_, device_id));
   device_id_to_observer_map_[device_id].Bind(std::move(observer));
 
@@ -248,6 +253,11 @@ void VideoCaptureHost::Resume(const base::UnguessableToken& device_id,
   DVLOG(1) << __func__ << " " << device_id;
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
+  if (!params.IsValid()) {
+    mojo::ReportBadMessage("Invalid video capture params.");
+    return;
+  }
+
   VideoCaptureControllerID controller_id(device_id);
   auto it = controllers_.find(controller_id);
   if (it == controllers_.end() || !it->second)