[Blink-Scheduler] Distinguish between normal and foreground-only renderers for monitoring load.

content/public/renderer/content_renderer_client.cc

Index: content/public/renderer/content_renderer_client.cc
diff --git a/content/public/renderer/content_renderer_client.cc b/content/public/renderer/content_renderer_client.cc
index 02565ee6d9900644820f16248ee65764722559aa..7ec391786dce43fdba0c8a6cd05ddd37006c4f36 100644
--- a/content/public/renderer/content_renderer_client.cc
+++ b/content/public/renderer/content_renderer_client.cc
@@ -249,4 +249,8 @@ bool ContentRendererClient::AllowMediaSuspend() {
   return true;
 }
 
+bool ContentRendererClient::CanBeBackgrounded() const {
+  return true;
+}
+
 }  // namespace content