VR: keep track of all pages that are recording audio/video/screen

chrome/browser/android/vr_shell/vr_shell.cc

 // Copyright 2016 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 "chrome/browser/android/vr_shell/vr_shell.h"
 
 #include <android/native_window_jni.h>
 
 #include <string>
 #include <utility>
@@ skipping 299 matching lines @@
 void VrShell::OnLoadProgressChanged(JNIEnv* env,
                                     const JavaParamRef<jobject>& obj,
                                     double progress) {
   ui_->SetLoadProgress(progress);
 }
 
 void VrShell::OnTabListCreated(JNIEnv* env,
                                const JavaParamRef<jobject>& obj,
                                jobjectArray tabs,
                                jobjectArray incognito_tabs) {
+  number_of_tabs_capturing_audio_ = 0;
+  number_of_tabs_capturing_video_ = 0;
+  number_of_tabs_capturing_screen_ = 0;
+
   ProcessTabArray(env, tabs, false);
   ProcessTabArray(env, incognito_tabs, true);
   ui_->FlushTabList();
 }
 
 void VrShell::ProcessTabArray(JNIEnv* env, jobjectArray tabs, bool incognito) {
   size_t len = env->GetArrayLength(tabs);
   for (size_t i = 0; i < len; ++i) {
     jobject jtab = env->GetObjectArrayElement(tabs, i);
     TabAndroid* tab =
         TabAndroid::GetNativeTab(env, JavaParamRef<jobject>(env, jtab));
     ui_->AppendToTabList(incognito, tab->GetAndroidId(), tab->GetTitle());
+    if (tab->web_contents() != web_contents_) {
+      scoped_refptr<MediaStreamCaptureIndicator> indicator =
+          MediaCaptureDevicesDispatcher::GetInstance()
+              ->GetMediaStreamCaptureIndicator();
+      if (indicator->IsCapturingAudio(tab->web_contents()))

[cjgrant, 2017/05/23 20:38:18]

If this method is reliable enough to use with other tabs, why not use it to
maintain the current tab's capture state as well?  This seems really clean.

[asimjour1, 2017/05/23 20:49:19]

Current tab can change its current state. So we have to poll the flag every 0.01
seconds. We don't need to do the same for the background tabs, so it will be
more efficient if we don't iterate on all tabs every 0.01 seconds.

[cjgrant, 2017/05/24 13:56:25]

A few more questions:
- Can a background tab ever change state?
- This code explicitly skips the current tab when counting right?  If that's the
case, won't it eliminate the current tab from being counted?  I'll message you
offline to understand this better.

[asimjour1, 2017/05/25 14:38:37]

I moved the code from here, and check all tabs every time.

+        number_of_tabs_capturing_audio_++;
+      if (indicator->IsCapturingVideo(tab->web_contents()))
+        number_of_tabs_capturing_video_++;
+      if (indicator->IsBeingMirrored(tab->web_contents()))
+        number_of_tabs_capturing_screen_++;
+    }
   }
 }
 
 void VrShell::OnTabUpdated(JNIEnv* env,
                            const JavaParamRef<jobject>& obj,
                            jboolean incognito,
                            jint id,
                            jstring jtitle) {
   std::string title;
   base::android::ConvertJavaStringToUTF8(env, jtitle, &title);
@@ skipping 225 matching lines @@
   poll_capturing_media_task_.Reset(
       base::Bind(&VrShell::PollMediaAccessFlag, base::Unretained(this)));
   main_thread_task_runner_->PostDelayedTask(
       FROM_HERE, poll_capturing_media_task_.callback(),
       poll_media_access_interval_);
 
   scoped_refptr<MediaStreamCaptureIndicator> indicator =
       MediaCaptureDevicesDispatcher::GetInstance()
           ->GetMediaStreamCaptureIndicator();
   bool is_capturing_audio = indicator->IsCapturingAudio(web_contents_);
-  if (is_capturing_audio != is_capturing_audio_)
-    ui_->SetAudioCapturingIndicator(is_capturing_audio);
+  if (is_capturing_audio != is_capturing_audio_) {
+    number_of_tabs_capturing_audio_ += is_capturing_audio ? 1 : -1;

[cjgrant, 2017/05/24 13:56:25]

style guide prefers "num_tabs_capturing_audio_" (and shorter is better :)  Then
its:
ui_->setAudiocapturingIndicator(num_tabs_... > 0);

[asimjour1, 2017/05/25 14:38:37]

Done.

+    if (number_of_tabs_capturing_audio_ > 0)
+      ui_->SetAudioCapturingIndicator(true);
+    else
+      ui_->SetAudioCapturingIndicator(false);
+  }
   is_capturing_audio_ = is_capturing_audio;
 
   bool is_capturing_video = indicator->IsCapturingVideo(web_contents_);
-  if (is_capturing_video != is_capturing_video_)
-    ui_->SetVideoCapturingIndicator(is_capturing_video);
+  if (is_capturing_video != is_capturing_video_) {
+    number_of_tabs_capturing_video_ += is_capturing_video ? 1 : -1;
+    if (number_of_tabs_capturing_video_ > 0)
+      ui_->SetVideoCapturingIndicator(true);
+    else
+      ui_->SetVideoCapturingIndicator(false);
+  }
   is_capturing_video_ = is_capturing_video;
 
   bool is_capturing_screen = indicator->IsBeingMirrored(web_contents_);
-  if (is_capturing_screen != is_capturing_screen_)
-    ui_->SetScreenCapturingIndicator(is_capturing_screen);
+  if (is_capturing_screen != is_capturing_screen_) {
+    number_of_tabs_capturing_screen_ += is_capturing_screen ? 1 : -1;
+    if (number_of_tabs_capturing_screen_ > 0)
+      ui_->SetScreenCapturingIndicator(true);
+    else
+      ui_->SetScreenCapturingIndicator(false);
+  }
   is_capturing_screen_ = is_capturing_screen;
 }
 
 void VrShell::SetContentCssSize(float width, float height, float dpr) {
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_VrShellImpl_setContentCssSize(env, j_vr_shell_.obj(), width, height,
                                      dpr);
 }
 
 void VrShell::ProcessContentGesture(
@@ skipping 44 matching lines @@
            jlong gvr_api,
            jboolean reprojected_rendering) {
   return reinterpret_cast<intptr_t>(new VrShell(
       env, obj, reinterpret_cast<ui::WindowAndroid*>(window_android),
       for_web_vr, in_cct,
       VrShellDelegate::GetNativeVrShellDelegate(env, delegate),
       reinterpret_cast<gvr_context*>(gvr_api), reprojected_rendering));
 }
 
 }  // namespace vr_shell