Use IpcVideoFrameCapturer on network thread instead of capturer thread.

remoting/host/basic_desktop_environment.h

Index: remoting/host/basic_desktop_environment.h
diff --git a/remoting/host/basic_desktop_environment.h b/remoting/host/basic_desktop_environment.h
index c99c8315468288d9ac9d4dd13a917e205ba1c2e3..85300615fce24925cbaad2c7d8950fd703c6d8f0 100644
--- a/remoting/host/basic_desktop_environment.h
+++ b/remoting/host/basic_desktop_environment.h
@@ -45,6 +45,7 @@ class BasicDesktopEnvironment : public DesktopEnvironment {
 
   BasicDesktopEnvironment(
       scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
+      scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> input_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
       bool supports_touch_events);
@@ -53,6 +54,11 @@ class BasicDesktopEnvironment : public DesktopEnvironment {
     return caller_task_runner_;
   }
 
+  scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner()
+      const {
+    return video_capture_task_runner_;
+  }
+
   scoped_refptr<base::SingleThreadTaskRunner> input_task_runner() const {
     return input_task_runner_;
   }
@@ -70,6 +76,9 @@ class BasicDesktopEnvironment : public DesktopEnvironment {
   // called.
   scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner_;
 
+  // Used to run video capturer.
+  scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner_;
+
   // Used to run input-related tasks.
   scoped_refptr<base::SingleThreadTaskRunner> input_task_runner_;
 
@@ -94,6 +103,7 @@ class BasicDesktopEnvironmentFactory : public DesktopEnvironmentFactory {
  public:
   BasicDesktopEnvironmentFactory(
       scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
+      scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> input_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
   ~BasicDesktopEnvironmentFactory() override;
@@ -110,6 +120,11 @@ class BasicDesktopEnvironmentFactory : public DesktopEnvironmentFactory {
     return caller_task_runner_;
   }
 
+  scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner()
+      const {
+    return video_capture_task_runner_;
+  }
+
   scoped_refptr<base::SingleThreadTaskRunner> input_task_runner() const {
     return input_task_runner_;
   }
@@ -125,6 +140,9 @@ class BasicDesktopEnvironmentFactory : public DesktopEnvironmentFactory {
   // be called.
   scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner_;
 
+  // Used to run video capture tasks.
+  scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner_;
+
   // Used to run input-related tasks.
   scoped_refptr<base::SingleThreadTaskRunner> input_task_runner_;