ResourceScheduler get visual signal from RenderViewHostImpl

content/browser/loader/resource_scheduler.cc

Index: content/browser/loader/resource_scheduler.cc
diff --git a/content/browser/loader/resource_scheduler.cc b/content/browser/loader/resource_scheduler.cc
index 85adbdb30e275631b53af88286e75b658e73a16c..7ce283eb2f67720fdb9bf5fd24ef168ba2035ff8 100644
--- a/content/browser/loader/resource_scheduler.cc
+++ b/content/browser/loader/resource_scheduler.cc
@@ -12,6 +12,7 @@
 #include "content/public/browser/resource_controller.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/resource_throttle.h"
+#include "content/public/browser/web_contents_observer.h"
 #include "ipc/ipc_message_macros.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/load_flags.h"
@@ -228,11 +229,11 @@ void ResourceScheduler::RequestQueue::Insert(
 }
 
 // Each client represents a tab.
-class ResourceScheduler::Client {
+class ResourceScheduler::Client : public content::WebContentsObserver {
  public:
-  explicit Client(ResourceScheduler* scheduler)
+  explicit Client(ResourceScheduler* scheduler, WebContentsImpl* web_contents)
       : is_audible_(false),
-        is_visible_(false),
+        is_visible_(!web_contents->IsHidden()),

[mmenke, 2014/08/15 18:57:09]

It's not safe to muck with the web_contents here.  We're on the IO thread, the
WebContents lives on the UI thread.

You're going to need some class that lives on the UI thread to observe the
events, and pass visibility change events over to the IO thread.

         is_loaded_(false),
         is_paused_(false),
         has_body_(false),
@@ -240,9 +241,10 @@ class ResourceScheduler::Client {
         total_delayable_count_(0),
         throttle_state_(ResourceScheduler::THROTTLED) {
     scheduler_ = scheduler;
+    Observe(web_contents);
   }
 
-  ~Client() {
+  virtual ~Client() {
     // Update to default state and pause to ensure the scheduler has a
     // correct count of relevant types of clients.
     is_visible_ = false;
@@ -251,6 +253,16 @@ class ResourceScheduler::Client {
     UpdateThrottleState();
   }
 
+  // WebContentsObserver implementation.
+  virtual void WasShown() OVERRIDE {
+    OnVisibilityChanged(true);
+  }
+
+  // WebContentsObserver implementation.
+  virtual void WasHidden() OVERRIDE {
+    OnVisibilityChanged(false);
+  }
+
   void ScheduleRequest(
       net::URLRequest* url_request,
       ScheduledResourceRequest* request) {
@@ -288,6 +300,8 @@ class ResourceScheduler::Client {
 
   bool is_loaded() const { return is_loaded_; }
 
+  bool IsVisible() const { return is_visible_; }
+
   void OnAudibilityChanged(bool is_audible) {
     if (is_audible == is_audible_) {
       return;
@@ -731,12 +745,14 @@ void ResourceScheduler::RemoveRequest(ScheduledResourceRequest* request) {
   client->RemoveRequest(request);
 }
 
-void ResourceScheduler::OnClientCreated(int child_id, int route_id) {
+void ResourceScheduler::OnClientCreated(int child_id,
+                                        int route_id,
+                                        WebContentsImpl* web_contents) {
   DCHECK(CalledOnValidThread());
   ClientId client_id = MakeClientId(child_id, route_id);
   DCHECK(!ContainsKey(client_map_, client_id));
 
-  Client* client = new Client(this);
+  Client* client = new Client(this, web_contents);
   client_map_[client_id] = client;
 
   // TODO(aiolos): set Client visibility/audibility when signals are added
@@ -817,14 +833,6 @@ void ResourceScheduler::OnAudibilityChanged(int child_id,
   client->OnAudibilityChanged(is_audible);
 }
 
-void ResourceScheduler::OnVisibilityChanged(int child_id,
-                                            int route_id,
-                                            bool is_visible) {
-  Client* client = GetClient(child_id, route_id);
-  DCHECK(client);
-  client->OnVisibilityChanged(is_visible);
-}
-
 void ResourceScheduler::OnLoadingStateChanged(int child_id,
                                               int route_id,
                                               bool is_loaded) {
@@ -833,6 +841,12 @@ void ResourceScheduler::OnLoadingStateChanged(int child_id,
   client->OnLoadingStateChanged(is_loaded);
 }
 
+bool ResourceScheduler::IsClientVisibleForTesting(int child_id, int route_id) {
+  Client* client = GetClient(child_id, route_id);
+  DCHECK(client);
+  return client->IsVisible();
+}
+
 ResourceScheduler::Client* ResourceScheduler::GetClient(int child_id,
                                                         int route_id) {
   ClientId client_id = MakeClientId(child_id, route_id);