Migrate //courgette to RepeatingCallback

This updates //courgette to use base::RepeatingCallback instead of
legacy base::Callback. No intended functional change is included.

This reduces the number of 'base::Bind' in //courgette from 3 to 0 as
tracked at http://goo.gl/LUVhDj

Bug: 714018
Change-Id: I40ec7c5cd7486f6b1110f13e35fd0368a4db9f3c
Reviewed-on: https://chromium-review.googlesource.com/954886
Reviewed-by: Samuel Huang <[email protected]>
Commit-Queue: Taiju Tsuiki <[email protected]>
Cr-Commit-Position: refs/heads/master@{#541735}
diff --git a/courgette/instruction_utils.h b/courgette/instruction_utils.h
index df12aa6..32287a9 100644
--- a/courgette/instruction_utils.h
+++ b/courgette/instruction_utils.h
@@ -59,7 +59,8 @@
 
 // A rerunable callback that emit instructions to a provided receptor. Returns
 // true on success, and false otherwise.
-using InstructionGenerator = base::Callback<CheckBool(InstructionReceptor*)>;
+using InstructionGenerator =
+    base::RepeatingCallback<CheckBool(InstructionReceptor*)>;
 
 // A counter that increments via .push_back(), so it can be passed via template
 // to substitute std::vector<T>, to count elements instead of storing them.