Split Android-specific dependency from BackgroundLoaderOffliner. Create a subfolder of c/b/offline_…

components/offline_pages/core/background/offliner.h

Index: components/offline_pages/core/background/offliner.h
diff --git a/components/offline_pages/core/background/offliner.h b/components/offline_pages/core/background/offliner.h
index c24aa46300745edaca26dcec929a82796cc605e7..20a953f5ae11d8c973e4bed89a4edf989634b690 100644
--- a/components/offline_pages/core/background/offliner.h
+++ b/components/offline_pages/core/background/offliner.h
@@ -97,6 +97,11 @@ class Offliner {
   // returns true and canceled request will be delivered using callback.
   virtual bool Cancel(const CancelCallback& callback) = 0;
 
+  // On some external condition changes (RAM pressure, browser backgrounded on
+  // low-level devices, etc) it is needed to terminate a load if there is one
+  // in progress. It is no-op if there is no active request loading.
+  virtual void TerminateLoadIfInProgress() = 0;
+
   // Handles timeout scenario. Returns true if lowbar is met and try to do a
   // snapshot of the current webcontents. If that is the case, the result of
   // offlining will be provided by |completion_callback|.