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..fe20526be0fb60d5aaf4fd03f4fb53332f015c50 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;
+  std::unique_ptr<ComponentInfo> GetComponentForMimeType(
+      const std::string& id) const override;
   OnDemandUpdater& GetOnDemandUpdater() override;
   void MaybeThrottle(const std::string& id,
                      const base::Closure& callback) override;
@@ -107,6 +109,11 @@ 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.
+  std::map<std::string, std::string> component_ids_by_mime_type_;
+
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(CrxUpdateService);