Add .clang-format and run clang-format on runtime/platform.

runtime/platform/text_buffer.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/text_buffer.h"
 
 #include "platform/assert.h"
 #include "platform/globals.h"
 #include "platform/utils.h"
 #include "vm/os.h"
@@ skipping 34 matching lines @@
 
 
 void TextBuffer::AddChar(char ch) {
   EnsureCapacity(sizeof(ch));
   buf_[msg_len_] = ch;
   msg_len_++;
   buf_[msg_len_] = '\0';
 }
 
 
-void TextBuffer::AddRaw(const uint8_t* buffer,
-                        intptr_t buffer_length) {
+void TextBuffer::AddRaw(const uint8_t* buffer, intptr_t buffer_length) {
   EnsureCapacity(buffer_length);
   memmove(&buf_[msg_len_], buffer, buffer_length);
   msg_len_ += buffer_length;
   buf_[msg_len_] = '\0';
 }
 
 
 intptr_t TextBuffer::Printf(const char* format, ...) {
   va_list args;
   va_start(args, format);
@@ skipping 90 matching lines @@
     char* new_buf = reinterpret_cast<char*>(realloc(buf_, new_size));
     if (new_buf == NULL) {
       OUT_OF_MEMORY();
     }
     buf_ = new_buf;
     buf_size_ = new_size;
   }
 }
 
 }  // namespace dart