Exit VR when our main content tab is hidden (Usually due to links opening in new tab)

chrome/browser/android/vr_shell/vr_shell.cc

Index: chrome/browser/android/vr_shell/vr_shell.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell.cc b/chrome/browser/android/vr_shell/vr_shell.cc
index 3b6261771756944e6825f63b80ae870cc8075ff3..8f980921abddf860ceb42c5226e44ec5cda4554f 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -1114,6 +1114,13 @@ void VrShell::ContentWebContentsDestroyed() {
   delegate_->ForceExitVr();
 }
 
+void VrShell::ContentWasHidden() {
+  // Ensure we don't continue sending input to it.
+  content_input_manager_.reset();
+  // TODO(mthiesse): Handle web contents being hidden.
+  delegate_->ForceExitVr();
+}
+
 void VrShell::SetContentCssSize(float width, float height, float dpr) {
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_VrShellImpl_setContentCssSize(env, j_vr_shell_.obj(), width, height,