Android: not to pause screen capture when Chrome is put to background

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 0c57eceedfeb4a5ff928e02c11661de31f1f4558..8e71cef4e68db4bc6fd3a4de3040ca504aa83b1f 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -84,6 +84,7 @@
 #include "content/renderer/input/input_handler_manager.h"
 #include "content/renderer/internal_document_state_data.h"
 #include "content/renderer/media/audio_device_factory.h"
+#include "content/renderer/media/media_stream_dispatcher.h"
 #include "content/renderer/media/video_capture_impl_manager.h"
 #include "content/renderer/navigation_state_impl.h"
 #include "content/renderer/render_frame_impl.h"
@@ -2278,8 +2279,8 @@ void RenderViewImpl::Close() {
 
 void RenderViewImpl::OnPageWasHidden() {
 #if defined(OS_ANDROID) && BUILDFLAG(ENABLE_WEBRTC)
-  RenderThreadImpl::current()->video_capture_impl_manager()->
-      SuspendDevices(true);
+  SuspendVideoCaptureDevices(true);
+
   if (speech_recognition_dispatcher_)
     speech_recognition_dispatcher_->AbortAllRecognitions();
 #endif
@@ -2298,8 +2299,7 @@ void RenderViewImpl::OnPageWasHidden() {
 
 void RenderViewImpl::OnPageWasShown() {
 #if defined(OS_ANDROID) && BUILDFLAG(ENABLE_WEBRTC)
-  RenderThreadImpl::current()->video_capture_impl_manager()->
-      SuspendDevices(false);
+  SuspendVideoCaptureDevices(false);
 #endif
 
   if (webview()) {
@@ -2568,6 +2568,26 @@ bool RenderViewImpl::didTapMultipleTargets(
 
   return handled;
 }
+
+void RenderViewImpl::SuspendVideoCaptureDevices(bool suspend) {

[tommi (sloooow) - chröme, 2017/03/21 09:21:17]

can we have a thread check for this function?

[braveyao, 2017/03/22 00:45:33]

There is no thread check yet in this file. Add thread check to this function
only or all the functions where thread check can apply?

[miu, 2017/03/22 23:09:42]

IMHO, it's not necessary: I think it's generally-known that RenderViewImpl runs
entirely on the main thread by default.

[braveyao, 2017/03/23 03:44:19]

Acknowledged.

+  if (!main_render_frame_)
+    return;
+
+  MediaStreamDispatcher* media_stream_dispatcher =
+      main_render_frame_->GetMediaStreamDispatcher();
+  if (media_stream_dispatcher) {

[tommi (sloooow) - chröme, 2017/03/21 09:21:18]

Could GetMediaStreamDispatcher() ever return null when
SuspendVideoCaptureDevices() is called?

[braveyao, 2017/03/22 00:45:33]

Just the codes[1] shows there is such possibility. Other place uses DCHECK. I
prefer real check. Hope it's OK.

[1]:https://cs.chromium.org/chromium/src/content/renderer/render_frame_impl.cc?type=cs&q=GetMediaStreamDispatcher&l=1473

+    StreamDeviceInfoArray video_array;
+    media_stream_dispatcher->GetVideoCaptureDevices(video_array);
+    for (const StreamDeviceInfo& device_it : video_array) {

[tommi (sloooow) - chröme, 2017/03/21 09:21:17]

|device_it| isn't correct. Suggest |device_info| instead.

[braveyao, 2017/03/22 00:45:33]

Done.

+      if (suspend)

[tommi (sloooow) - chröme, 2017/03/21 09:21:17]

use {} as per coding guidelines

[braveyao, 2017/03/22 00:45:33]

Done.

+        RenderThreadImpl::current()->video_capture_impl_manager()->Suspend(
+            device_it.session_id);
+      else
+        RenderThreadImpl::current()->video_capture_impl_manager()->Resume(
+            device_it.session_id);
+    }
+  }
+}
 #endif  // defined(OS_ANDROID)
 
 unsigned RenderViewImpl::GetLocalSessionHistoryLengthForTesting() const {