[Layout] Layout API based on content area (#2110)

* Initial commit for adding a size constraint to ASLayoutable's

* Some more commits

* Fix sample projects in extra/

* Remove preferredFrameSize test of ASEditableTextNode

* Remove preferredFrameSize from examples_extra

* Add deprecation warning to -[ASDisplayNode preferredFrameSize]

* Add deprecation warning to -[ASDisplayNode measureWithSizeRange:]

* Commit

* Commit

* Remove ASRelativeSizeRange

* Make ASRelativeSize private

* Adjust examples

* Improve setting of -[ASLayoutable size] with points or fractions

* Add ASWrapperLayoutSpec

* Improve creation of ASRelativeDimension

* Add `preferredFrameSize` back and add deprecated logging

* Add `layoutSpecBlock` setter and getter and add locking for it

* Add better documentation and fix macros to create ASRelativeDimension

* Create new ASSizeRangeMake with just a CGSize as parameter

* Update Kitten and Social App Layout example

* Add layoutThatFits: and deprecate measure:

* Rename ASRelativeDimension to ASDimension

* Fix examples for ASDimension renaming

* Remove fancy height and width setter

* Fix ASDimension helper

* Rename -[ASLayout layoutableObject] to -[ASLayout layoutable]

* Update layout related methods and more clearer documentation around how to use it

* Deprecate old ASLayout class constructors

* Don't unnecessary recalculate layout if constrained or parent size did not change

* Use shared pointer for ASDisplayNodeLayout

* Fix rebase conflicts

* Add documentation and move implementation in mm file of ASDisplayNodeLayout

* Fix test errors

* Rename ASSize to ASLayoutableSize

* Address comments

* Rename setSizeFromCGSize to setSizeWithCGSize

* Improve inline functions in ASDimension

* Fix rebase conflicts

AsyncDisplayKit/Private/ASDisplayNodeLayout.mm

@@ -0,0 +1,34 @@
+//
+//  ASDisplayNodeLayout.mm
+//  AsyncDisplayKit
+//
+//  Created by Michael Schneider on 08/26/16.
+//
+//  Copyright (c) 2014-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+
+#include "ASDisplayNodeLayout.h"
+
+BOOL ASDisplayNodeLayout::isDirty()
+{
+  return _dirty || layout == nil;
+}
+
+BOOL ASDisplayNodeLayout::isValidForConstrainedSizeParentSize(ASSizeRange theConstrainedSize, CGSize theParentSize)
+{
+  // Only generate a new layout if:
+  // - The current layout is dirty
+  // - The passed constrained size is different than the original layout's parent or constrained  size
+  return (layout != nil
+          && _dirty == NO
+          && CGSizeEqualToSize(parentSize, theParentSize)
+          && ASSizeRangeEqualToSizeRange(constrainedSize, theConstrainedSize));
+}
+
+void ASDisplayNodeLayout::invalidate()
+{
+  _dirty = YES;
+}