Implement Just-In-Time Flash updates.

components/component_updater/component_updater_service_internal.h

Index: components/component_updater/component_updater_service_internal.h
diff --git a/components/component_updater/component_updater_service_internal.h b/components/component_updater/component_updater_service_internal.h
index e20a3156fadda9380535ddf2a1c55ffb185c2956..86782c2130429f058e6f1df57b4c48e42ec78a2b 100644
--- a/components/component_updater/component_updater_service_internal.h
+++ b/components/component_updater/component_updater_service_internal.h
@@ -43,6 +43,8 @@ class CrxUpdateService : public ComponentUpdateService,
   bool RegisterComponent(const CrxComponent& component) override;
   bool UnregisterComponent(const std::string& id) override;
   std::vector<std::string> GetComponentIDs() const override;
+  bool GetComponentForMimeType(const std::string& id,
+                               ComponentInfo* info) const override;
   OnDemandUpdater& GetOnDemandUpdater() override;
   void MaybeThrottle(const std::string& id,
                      const base::Closure& callback) override;
@@ -107,6 +109,12 @@ class CrxUpdateService : public ComponentUpdateService,
   using ComponentStates = std::map<std::string, CrxUpdateItem>;
   ComponentStates component_states_;
 
+  // Contains a map of media types to the component that implements a handler
+  // for that media type. Only the most recently-registered component is
+  // tracked. May include the IDs of un-registered components.
+  using ComponentIdsByMimeType = std::map<std::string, std::string>;

[Bernhard Bauer, 2016/07/28 10:25:10]

Nit: This type is never used anywhere else, and it's not much shorter than the
full type... :)

[waffles, 2016/07/28 20:06:27]

Done.

+  ComponentIdsByMimeType component_ids_by_mime_type_;
+
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(CrxUpdateService);