Replace manual casting to rvalue reference with calls to std::move

Review URL: https://codereview.webrtc.org/1570473002

Cr-Commit-Position: refs/heads/master@{#11163}

webrtc/base/buffer.h

@@ -172,7 +172,7 @@ class Buffer {
   // b.Pass() does the same thing as std::move(b).
   Buffer&& Pass() {
     assert(IsConsistent());
-    return static_cast<Buffer&&>(*this);
+    return std::move(*this);
   }
 
   // Resets the buffer to zero size and capacity. Works even if the buffer has

webrtc/base/optional.h

@@ -66,20 +66,19 @@ class Optional final {
 
   // Construct an Optional that contains a value.
   explicit Optional(const T& val) : value_(val), has_value_(true) {}
-  explicit Optional(T&& val)
-      : value_(static_cast<T&&>(val)), has_value_(true) {}
+  explicit Optional(T&& val) : value_(std::move(val)), has_value_(true) {}
 
   // Copy and move constructors.
   // TODO(kwiberg): =default the move constructor when MSVC supports it.
   Optional(const Optional&) = default;
   Optional(Optional&& m)
-      : value_(static_cast<T&&>(m.value_)), has_value_(m.has_value_) {}
+      : value_(std::move(m.value_)), has_value_(m.has_value_) {}
 
   // Assignment.
   // TODO(kwiberg): =default the move assignment op when MSVC supports it.
   Optional& operator=(const Optional&) = default;
   Optional& operator=(Optional&& m) {
-    value_ = static_cast<T&&>(m.value_);
+    value_ = std::move(m.value_);
     has_value_ = m.has_value_;
     return *this;
   }

webrtc/base/optional_unittest.cc

@@ -162,7 +162,7 @@ TEST(OptionalTest, TestConstructMoveEmpty) {
   {
     Optional<Logger> x;
     EXPECT_FALSE(x);
-    auto y = static_cast<Optional<Logger>&&>(x);
+    auto y = std::move(x);
     EXPECT_FALSE(y);
   }
   EXPECT_EQ(V("0:0. default constructor", "1:0. move constructor (from 0:0)",
@@ -176,7 +176,7 @@ TEST(OptionalTest, TestConstructMoveFull) {
     Optional<Logger> x(Logger(17));
     EXPECT_TRUE(x);
     log->push_back("---");
-    auto y = static_cast<Optional<Logger>&&>(x);
+    auto y = std::move(x);
     EXPECT_TRUE(x);
     EXPECT_TRUE(y);
     log->push_back("---");
@@ -289,7 +289,7 @@ TEST(OptionalTest, TestMoveAssignToEmptyFromEmpty) {
   auto log = Logger::Setup();
   {
     Optional<Logger> x, y;
-    x = static_cast<Optional<Logger>&&>(y);
+    x = std::move(y);
   }
   EXPECT_EQ(
       V("0:0. default constructor", "1:1. default constructor",
@@ -303,7 +303,7 @@ TEST(OptionalTest, TestMoveAssignToFullFromEmpty) {
     Optional<Logger> x(Logger(17));
     Optional<Logger> y;
     log->push_back("---");
-    x = static_cast<Optional<Logger>&&>(y);
+    x = std::move(y);
     log->push_back("---");
   }
   EXPECT_EQ(
@@ -320,7 +320,7 @@ TEST(OptionalTest, TestMoveAssignToEmptyFromFull) {
     Optional<Logger> x;
     Optional<Logger> y(Logger(17));
     log->push_back("---");
-    x = static_cast<Optional<Logger>&&>(y);
+    x = std::move(y);
     log->push_back("---");
   }
   EXPECT_EQ(V("0:0. default constructor", "1:17. explicit constructor",
@@ -336,7 +336,7 @@ TEST(OptionalTest, TestMoveAssignToFullFromFull) {
     Optional<Logger> x(Logger(17));
     Optional<Logger> y(Logger(42));
     log->push_back("---");
-    x = static_cast<Optional<Logger>&&>(y);
+    x = std::move(y);
     log->push_back("---");
   }
   EXPECT_EQ(
@@ -354,7 +354,7 @@ TEST(OptionalTest, TestMoveAssignToEmptyFromT) {
     Optional<Logger> x;
     Logger y(17);
     log->push_back("---");
-    x = Optional<Logger>(static_cast<Logger&&>(y));
+    x = Optional<Logger>(std::move(y));
     log->push_back("---");
   }
   EXPECT_EQ(V("0:0. default constructor", "1:17. explicit constructor", "---",
@@ -370,7 +370,7 @@ TEST(OptionalTest, TestMoveAssignToFullFromT) {
     Optional<Logger> x(Logger(17));
     Logger y(42);
     log->push_back("---");
-    x = Optional<Logger>(static_cast<Logger&&>(y));
+    x = Optional<Logger>(std::move(y));
     log->push_back("---");
   }
   EXPECT_EQ(
@@ -390,13 +390,13 @@ TEST(OptionalTest, TestDereference) {
     log->push_back("---");
     x->Foo();
     y->Foo();
-    static_cast<Optional<Logger>&&>(x)->Foo();
-    static_cast<const Optional<Logger>&&>(y)->Foo();
+    std::move(x)->Foo();
+    std::move(y)->Foo();
     log->push_back("---");
     (*x).Foo();
     (*y).Foo();
-    (*static_cast<Optional<Logger>&&>(x)).Foo();
-    (*static_cast<const Optional<Logger>&&>(y)).Foo();
+    (*std::move(x)).Foo();
+    (*std::move(y)).Foo();
     log->push_back("---");
   }
   EXPECT_EQ(V("0:42. explicit constructor",

webrtc/base/scoped_ptr.h

@@ -374,7 +374,7 @@ class scoped_ptr {
   scoped_ptr& operator=(const scoped_ptr& other) = delete;
 
   // Get an rvalue reference. (sp.Pass() does the same thing as std::move(sp).)
-  scoped_ptr&& Pass() { return static_cast<scoped_ptr&&>(*this); }
+  scoped_ptr&& Pass() { return std::move(*this); }
 
   // Reset.  Deletes the currently owned object, if any.
   // Then takes ownership of a new object, if given.
@@ -507,7 +507,7 @@ class scoped_ptr<T[], D> {
   scoped_ptr& operator=(const scoped_ptr& other) = delete;
 
   // Get an rvalue reference. (sp.Pass() does the same thing as std::move(sp).)
-  scoped_ptr&& Pass() { return static_cast<scoped_ptr&&>(*this); }
+  scoped_ptr&& Pass() { return std::move(*this); }
 
   // Reset.  Deletes the currently owned array, if any.
   // Then takes ownership of a new object, if given.

webrtc/system_wrappers/include/scoped_vector.h

@@ -43,9 +43,7 @@ class ScopedVector {
   ~ScopedVector() { clear(); }
 
   // Move construction and assignment.
-  ScopedVector(ScopedVector&& other) {
-    *this = static_cast<ScopedVector&&>(other);
-  }
+  ScopedVector(ScopedVector&& other) { *this = std::move(other); }
   ScopedVector& operator=(ScopedVector&& other) {
     std::swap(v_, other.v_);  // The arguments are std::vectors, so std::swap
                               // is the one that we want.
@@ -58,7 +56,7 @@ class ScopedVector {
   ScopedVector& operator=(const ScopedVector& other) = delete;
 
   // Get an rvalue reference. (sv.Pass() does the same thing as std::move(sv).)
-  ScopedVector&& Pass() { return static_cast<ScopedVector&&>(*this); }
+  ScopedVector&& Pass() { return std::move(*this); }
 
   reference operator[](size_t index) { return v_[index]; }
   const_reference operator[](size_t index) const { return v_[index]; }