Remove unused clobber_active_value getter.

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I100467a0c95efe3c686ae5e79e1e6e8da32b39ec
Reviewed-on: https://chromium-review.googlesource.com/600823Reviewed-by: Vladimir Levin <vmpstr@chromium.org>
Commit-Queue: Walter Korman <wkorman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491946}

cc/base/synced_property.h

@@ -112,7 +112,6 @@ class SyncedProperty : public base::RefCounted<SyncedProperty<T>> {
   }
 
   void set_clobber_active_value() { clobber_active_value_ = true; }
-  bool clobber_active_value() const { return clobber_active_value_; }
 
  private:
   // Value last committed to the pending tree.