Refactor IntersectionGeometry class and move it to core/layout.

third_party/WebKit/Source/core/layout/BUILD.gn

 # Copyright 2016 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.
 
 import("//third_party/WebKit/Source/core/core.gni")
 
 blink_core_sources("layout") {
   split_count = 5
 
   sources = [
@@ skipping 21 matching lines @@
     "HitTestCache.cpp",
     "HitTestCache.h",
     "HitTestCanvasResult.cpp",
     "HitTestLocation.cpp",
     "HitTestLocation.h",
     "HitTestResult.cpp",
     "HitTestingTransformState.cpp",
     "HitTestingTransformState.h",
     "ImageQualityController.cpp",
     "ImageQualityController.h",
+    "IntersectionGeometry.cpp",
+    "IntersectionGeometry.h",
     "LayoutAnalyzer.cpp",
     "LayoutAnalyzer.h",
     "LayoutBR.cpp",
     "LayoutBlock.cpp",
     "LayoutBlockFlow.cpp",
     "LayoutBlockFlowLine.cpp",
     "LayoutBox.cpp",
     "LayoutBoxModelObject.cpp",
     "LayoutButton.cpp",
     "LayoutButton.h",
@@ skipping 320 matching lines @@
       "LayoutThemeAndroid.cpp",
       "LayoutThemeAndroid.h",
     ]
   }
 
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }