Convert Pass()→std::move() in //mojo/public/

mojo/public/cpp/bindings/array.h

Index: mojo/public/cpp/bindings/array.h
diff --git a/mojo/public/cpp/bindings/array.h b/mojo/public/cpp/bindings/array.h
index f7d392178b3f0dfa9bb56336ea81307d2565d270..435f6b81c0deed190ce77c000425b450d5e4f3ed 100644
--- a/mojo/public/cpp/bindings/array.h
+++ b/mojo/public/cpp/bindings/array.h
@@ -6,10 +6,10 @@
 #define MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_
 
 #include <string.h>
-
 #include <algorithm>
 #include <set>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "mojo/public/cpp/bindings/lib/array_internal.h"
@@ -56,7 +56,7 @@ class Array {
   // Creates a non-null array of the specified size. The elements will be
   // value-initialized (meaning that they will be initialized by their default
   // constructor, if any, or else zero-initialized).
-  static Array New(size_t size) { return Array(size).Pass(); }
+  static Array New(size_t size) { return std::move(Array(size)); }

[Ken Rockot(use gerrit already), 2015/12/21 18:49:22]

Shouldn't clang complain that moving a temporary prevents copy elision (here and
elsewhere)? Why is this necessary? I remember we were calling Pass() before
because MSVC choked otherwise, but I didn't know if that was still an issue.

[dcheng, 2015/12/21 19:27:27]

It does in many instances: you'll notice that some of the diffs just deleted
Pass() instead of changing it to std::move().

However, I'm not sure why this particular instance didn't trigger the warning:
it certainly looks like it should. We had similar issues with scoped_ptr.h which
were diagnosed as a failure to have an actual move constructor, but that doesn't
appear to be the case here.

As these patches are largely automated, I'd prefer not to fix things the
compiler doesn't warn about (though this particular instance is quite odd, and
I'll be follow up on it separately anyway).

 
   // Creates a new array with a copy of the contents of |other|.
   template <typename U>
@@ -145,7 +145,7 @@ class Array {
     Array result;
     result.is_null_ = is_null_;
     Traits::Clone(vec_, &result.vec_);
-    return result.Pass();
+    return std::move(result);
   }
 
   // Indicates whether the contents of this array are equal to |other|. A null
@@ -196,7 +196,7 @@ struct TypeConverter<Array<T>, std::vector<E>> {
     Array<T> result(input.size());
     for (size_t i = 0; i < input.size(); ++i)
       result[i] = TypeConverter<T, E>::Convert(input[i]);
-    return result.Pass();
+    return std::move(result);
   }
 };
 
@@ -225,7 +225,7 @@ struct TypeConverter<Array<T>, std::set<E>> {
     Array<T> result(0u);
     for (auto i : input)
       result.push_back(TypeConverter<T, E>::Convert(i));
-    return result.Pass();
+    return std::move(result);
   }
 };