Mojo: clang-format mojo/public/c/... and add a presubmit check.

mojo/public/c/system/macros.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_C_SYSTEM_MACROS_H_
 #define MOJO_PUBLIC_C_SYSTEM_MACROS_H_
 
 #include <stddef.h>
 
 // Annotate a variable indicating it's okay if it's unused.
@@ skipping 17 matching lines @@
 
 #ifdef __cplusplus
 // Used to explicitly mark the return value of a function as unused. If you are
 // really sure you don't want to do anything with the return value of a function
 // that has been marked WARN_UNUSED_RESULT, wrap it with this. Example:
 //
 //   scoped_ptr<MyType> my_var = ...;
 //   if (TakeOwnership(my_var.get()) == SUCCESS)
 //     mojo_ignore_result(my_var.release());
 //
-template<typename T>
+template <typename T>
 inline void mojo_ignore_result(const T&) {
 }
 #endif
 
 // Assert things at compile time. (|msg| should be a valid identifier name.)
 // This macro is currently C++-only, but we want to use it in the C core.h.
 // Use like:
 //   MOJO_COMPILE_ASSERT(sizeof(Foo) == 12, Foo_has_invalid_size);
 #if __cplusplus >= 201103L
 #define MOJO_COMPILE_ASSERT(expr, msg) static_assert(expr, #msg)
 #elif defined(__cplusplus)
-namespace mojo { template <bool> struct CompileAssert {}; }
+namespace mojo {
+template <bool>
+struct CompileAssert {};
+}
 #define MOJO_COMPILE_ASSERT(expr, msg) \
-    typedef ::mojo::CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
+  typedef ::mojo::CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
 #else
 #define MOJO_COMPILE_ASSERT(expr, msg)
 #endif
 
 // Like the C++11 |alignof| operator.
 #if __cplusplus >= 201103L
 #define MOJO_ALIGNOF(type) alignof(type)
 #elif defined(__GNUC__)
 #define MOJO_ALIGNOF(type) __alignof__(type)
 #elif defined(_MSC_VER)
@@ skipping 14 matching lines @@
 #define MOJO_ALIGNAS(alignment) alignas(alignment)
 #elif defined(__GNUC__)
 #define MOJO_ALIGNAS(alignment) __attribute__((aligned(alignment)))
 #elif defined(_MSC_VER)
 #define MOJO_ALIGNAS(alignment) __declspec(align(alignment))
 #else
 #error "Please define MOJO_ALIGNAS() for your compiler."
 #endif
 
 #endif  // MOJO_PUBLIC_C_SYSTEM_MACROS_H_