ResourceScheduler get visual signal from RenderViewHostImpl

content/browser/loader/resource_scheduler.h

Index: content/browser/loader/resource_scheduler.h
diff --git a/content/browser/loader/resource_scheduler.h b/content/browser/loader/resource_scheduler.h
index 74ac16d3d42be6fa23f226b134817d030364d3c1..d8bb2c6a2a5473bf5e762f42cbbbae68fdb707ff 100644
--- a/content/browser/loader/resource_scheduler.h
+++ b/content/browser/loader/resource_scheduler.h
@@ -13,6 +13,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/timer/timer.h"
+#include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/content_export.h"
 #include "net/base/priority_queue.h"
 #include "net/base/request_priority.h"
@@ -81,6 +82,14 @@ class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
   ResourceScheduler();
   ~ResourceScheduler();
 
+  // VisualObserver observes WebContents and lives on the UI thread. It notifies
+  // the client about the visibility change. Each VisualObserver corresponds to
+  // one and only one Client. The VisualObserver will be deleted when the client
+  // is destructed.
+  class VisualObserver;
+  VisualObserver* CreateVisualObserver(WebContentsImpl* web_content);
+  void DeleteVisualObserver(VisualObserver* observer);
+
   // Use a mock timer when testing.
   void set_timer_for_testing(scoped_ptr<base::Timer> timer) {
     coalescing_timer_.reset(timer.release());
@@ -103,9 +112,13 @@ class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
   // Signals from the UI thread, posted as tasks on the IO thread:
 
   // Called when a renderer is created.
-  void OnClientCreated(int child_id, int route_id);
+  void OnClientCreated(int child_id,
+                       int route_id,
+                       VisualObserver* visual_observer,
+                       bool is_visible);
 
-  // Called when a renderer is destroyed.
+  // Called when a renderer is destroyed. It will also delete the corresponding
+  // VisualObserver in turn.
   void OnClientDeleted(int child_id, int route_id);
 
   // Signals from IPC messages directly from the renderers:
@@ -131,11 +144,10 @@ class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
   // Called when a Client starts or stops playing audio.
   void OnAudibilityChanged(int child_id, int route_id, bool is_audible);
 
-  // Called when a Client is shown or hidden.
-  void OnVisibilityChanged(int child_id, int route_id, bool is_visible);
-
   void OnLoadingStateChanged(int child_id, int route_id, bool is_loaded);
 
+  bool IsClientVisibleForTesting(int child_id, int route_id);
+
  private:
   class RequestQueue;
   class ScheduledResourceRequest;