Revert of Remove ForceReclaimResources

cc/output/compositor_frame_sink.h

Index: cc/output/compositor_frame_sink.h
diff --git a/cc/output/compositor_frame_sink.h b/cc/output/compositor_frame_sink.h
index b85c8bca846e5db483327ed958d6bb91e39c3333..333363fdc761f2eeea9b5c9dfde05344ae7d91f9 100644
--- a/cc/output/compositor_frame_sink.h
+++ b/cc/output/compositor_frame_sink.h
@@ -40,13 +40,9 @@
   struct Capabilities {
     Capabilities() = default;
 
-    // True if we must always swap, even if there is no damage to the frame.
-    // Needed for both the browser compositor as well as layout tests.
-    // TODO(ericrk): This should be test-only for layout tests, but tab
-    // capture has issues capturing offscreen tabs whithout this. We should
-    // remove this dependency. crbug.com/680196
-    bool must_always_swap = false;
-
+    // Whether ForceReclaimResources can be called to reclaim all resources
+    // from the CompositorFrameSink.
+    bool can_force_reclaim_resources = false;
     // True if sync points for resources are needed when swapping delegated
     // frames.
     bool delegated_sync_points_required = true;
@@ -105,6 +101,10 @@
     return shared_bitmap_manager_;
   }
 
+  // If supported, this causes a ReclaimResources for all resources that are
+  // currently in use.
+  virtual void ForceReclaimResources() {}
+
   // Support for a pull-model where draws are requested by the output surface.
   //
   // CompositorFrameSink::Invalidate is called by the compositor to notify that