MediaRouter: Cache MediaRoutesObserver queries to prevent ext wake-ups

chrome/browser/media/router/mojo/media_router_mojo_impl.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_MEDIA_ROUTER_MOJO_MEDIA_ROUTER_MOJO_IMPL_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_MOJO_MEDIA_ROUTER_MOJO_IMPL_H_
 
 #include <stdint.h>
 
 #include <deque>
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "base/containers/hash_tables.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "base/optional.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "chrome/browser/media/router/issue.h"
 #include "chrome/browser/media/router/issue_manager.h"
 #include "chrome/browser/media/router/media_router_base.h"
 #include "chrome/browser/media/router/media_routes_observer.h"
 #include "chrome/browser/media/router/mojo/media_router.mojom.h"
 #include "chrome/browser/media/router/route_request_result.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
@@ skipping 130 matching lines @@
   // Represents a query to the MRPM for media sinks and holds observers for the
   // query.
   struct MediaSinksQuery {
    public:
     MediaSinksQuery();
     ~MediaSinksQuery();
 
     // True if the query has been sent to the MRPM.
     bool is_active = false;
 
-    // True if cached result is available.
-    bool has_cached_result = false;
+    // Cached list of sinks and origins for the query.
+    base::Optional<std::vector<MediaSink>> cached_sink_list;
+    std::vector<url::Origin> origins;
 
-    // Cached list of sinks for the query, if |has_cached_result| is true.
-    // Empty otherwise.
-    std::vector<MediaSink> cached_sink_list;
-    std::vector<url::Origin> origins;
     base::ObserverList<MediaSinksObserver> observers;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(MediaSinksQuery);
   };
 
   struct MediaRoutesQuery {
    public:
     MediaRoutesQuery();
     ~MediaRoutesQuery();
 
     // True if the query has been sent to the MRPM.  False otherwise.
     bool is_active = false;
+
+    // Cached list of routes and joinable route IDs for the query.
+    base::Optional<std::vector<MediaRoute>> cached_route_list;
+    std::vector<std::string> joinable_route_ids;
+
     base::ObserverList<MediaRoutesObserver> observers;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(MediaRoutesQuery);
   };
 
   // Standard constructor, used by
   // MediaRouterMojoImplFactory::GetApiForBrowserContext.
   explicit MediaRouterMojoImpl(
       extensions::EventPageTracker* event_page_tracker);
@@ skipping 22 matching lines @@
   // MediaRouter implementation.
   bool RegisterMediaSinksObserver(MediaSinksObserver* observer) override;
   void UnregisterMediaSinksObserver(MediaSinksObserver* observer) override;
   void RegisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
   void UnregisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
   void RegisterIssuesObserver(IssuesObserver* observer) override;
   void UnregisterIssuesObserver(IssuesObserver* observer) override;
   void RegisterRouteMessageObserver(RouteMessageObserver* observer) override;
   void UnregisterRouteMessageObserver(RouteMessageObserver* observer) override;
 
+  // Notifies |observer| of any existing cached routes, if it is still
+  // registered.
+  void NotifyOfExistingRoutesIfRegistered(const MediaSource::Id& source_id,
+                                          MediaRoutesObserver* observer) const;
+
   // These calls invoke methods in the component extension via Mojo.
   void DoCreateRoute(const MediaSource::Id& source_id,
                      const MediaSink::Id& sink_id,
                      const url::Origin& origin,
                      int tab_id,
                      const std::vector<MediaRouteResponseCallback>& callbacks,
                      base::TimeDelta timeout,
                      bool incognito);
   void DoJoinRoute(const MediaSource::Id& source_id,
                    const std::string& presentation_id,
@@ skipping 185 matching lines @@
 #endif
 
   base::WeakPtrFactory<MediaRouterMojoImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterMojoImpl);
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MOJO_MEDIA_ROUTER_MOJO_IMPL_H_