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

content/renderer/render_view_impl.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/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 
@@ skipping 66 matching lines @@
 #include "content/renderer/browser_plugin/browser_plugin_manager.h"
 #include "content/renderer/dom_storage/webstoragenamespace_impl.h"
 #include "content/renderer/drop_data_builder.h"
 #include "content/renderer/gpu/render_widget_compositor.h"
 #include "content/renderer/history_serialization.h"
 #include "content/renderer/idle_user_detector.h"
 #include "content/renderer/ime_event_guard.h"
 #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"
 #include "content/renderer/render_frame_proxy.h"
 #include "content/renderer/render_process.h"
 #include "content/renderer/render_thread_impl.h"
 #include "content/renderer/render_widget_fullscreen_pepper.h"
 #include "content/renderer/renderer_webapplicationcachehost_impl.h"
 #include "content/renderer/resizing_mode_selector.h"
 #include "content/renderer/savable_resources.h"
@@ skipping 2174 matching lines @@
   WebView* doomed = webview_;
   RenderWidget::Close();
   webview_ = nullptr;
   g_view_map.Get().erase(doomed);
   g_routing_id_view_map.Get().erase(GetRoutingID());
   RenderThread::Get()->Send(new ViewHostMsg_Close_ACK(GetRoutingID()));
 }
 
 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
 
   if (webview()) {
     // TODO(lfg): It's not correct to defer the page visibility to the main
     // frame. Currently, this is done because the main frame may override the
     // visibility of the page when prerendering. In order to fix this,
     // prerendering must be made aware of OOPIFs. https://crbug.com/440544
     blink::WebPageVisibilityState visibilityState =
         GetMainRenderFrame() ? GetMainRenderFrame()->visibilityState()
                              : blink::WebPageVisibilityStateHidden;
     webview()->setVisibilityState(visibilityState, false);
   }
 }
 
 void RenderViewImpl::OnPageWasShown() {
 #if defined(OS_ANDROID) && BUILDFLAG(ENABLE_WEBRTC)
-  RenderThreadImpl::current()->video_capture_impl_manager()->
-      SuspendDevices(false);
+  SuspendVideoCaptureDevices(false);
 #endif
 
   if (webview()) {
     blink::WebPageVisibilityState visibilityState =
         GetMainRenderFrame() ? GetMainRenderFrame()->visibilityState()
                              : blink::WebPageVisibilityStateVisible;
     webview()->setVisibilityState(visibilityState, false);
   }
 }
 
@@ skipping 248 matching lines @@
       handled = true;
       break;
     }
     case TAP_MULTIPLE_TARGETS_STRATEGY_NONE:
       // No-op.
       break;
   }
 
   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 {
   return history_list_length_;
 }
 
 void RenderViewImpl::SetFocusAndActivateForTesting(bool enable) {
   if (enable) {
     if (has_focus())
       return;
@@ skipping 131 matching lines @@
                             INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   }
 
   std::unique_ptr<InputEventAck> ack(
       new InputEventAck(InputEventAckSource::MAIN_THREAD, input_event->type(),
                         INPUT_EVENT_ACK_STATE_NOT_CONSUMED));
   OnInputEventAck(std::move(ack));
 }
 
 }  // namespace content