[LayoutNG] Implement bidi adjustment for SelectionController

This patch generalizes RenderedPosition to store an AbsoluteInlineBox,
so that it also works with LayoutNG. As a result, bidi adjustment for
SelectionController is enabled in LayoutNG.

Bug: 811502
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_layout_ng;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I27d2ebe8e091173c4d298f15eb47b60f76c15312
Reviewed-on: https://chromium-review.googlesource.com/1070564Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561612}

third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-features=LayoutNG

@@ -43,10 +43,6 @@ crbug.com/591099 fast/css/getComputedStyle/getComputedStyle-resolved-values.html
 # https://cs.chromium.org/chromium/src/third_party/blink/renderer/core/layout/layout_block.cc?l=1372&rcl=0e081149ecd6a83f6289e3aee5797936008a1e10
 crbug.com/591099 fast/block/marquee-width-shrinks-to-fit-in-fixed-size-container.html [ Failure ]
 
-# Needs bidi adjustment for SelectionController
-crbug.com/811502 editing/selection/mouse/drag_selects_bidi_image.html [ Failure ]
-crbug.com/811502 fast/text/selection/hebrew-selection.html [ Failure ]
-
 # New passes
 crbug.com/591099 external/wpt/css/CSS2/floats-clear/no-clearance-adjoining-opposite-float.html [ Pass ]
 crbug.com/591099 external/wpt/css/CSS2/floats-clear/no-clearance-due-to-large-margin-after-left-right.html [ Pass ]
@@ -213,7 +209,6 @@ crbug.com/714962 editing/selection/offset-from-point-complex-scripts.html [ Fail
 crbug.com/714962 editing/selection/offset-from-point.html [ Failure Pass ]
 crbug.com/591099 editing/selection/paint-hyphen.html [ Failure ]
 crbug.com/591099 editing/selection/programmatic-selection-on-mac-is-directionless.html [ Timeout ]
-crbug.com/591099 editing/selection/select-bidi-run.html [ Failure ]
 crbug.com/591099 editing/selection/selection-button-text.html [ Failure Pass ]
 crbug.com/591099 editing/selection/skip-over-contenteditable.html [ Failure ]
 crbug.com/591099 editing/selection/transformed-selection-rects.html [ Failure Pass ]

third_party/blink/renderer/core/editing/ng_flat_tree_shorthands.cc

@@ -7,6 +7,7 @@
 #include "third_party/blink/renderer/core/editing/local_caret_rect.h"
 #include "third_party/blink/renderer/core/editing/position.h"
 #include "third_party/blink/renderer/core/editing/position_with_affinity.h"
+#include "third_party/blink/renderer/core/layout/ng/inline/ng_caret_position.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_caret_rect.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_line_utils.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_offset_mapping.h"
@@ -18,6 +19,11 @@ const LayoutBlockFlow* NGInlineFormattingContextOf(
   return NGInlineFormattingContextOf(ToPositionInDOMTree(position));
 }
 
+NGCaretPosition ComputeNGCaretPosition(
+    const PositionInFlatTreeWithAffinity& position) {
+  return ComputeNGCaretPosition(ToPositionInDOMTreeWithAffinity(position));
+}
+
 LocalCaretRect ComputeNGLocalCaretRect(
     const PositionInFlatTreeWithAffinity& position) {
   return ComputeNGLocalCaretRect(ToPositionInDOMTreeWithAffinity(position));

third_party/blink/renderer/core/editing/ng_flat_tree_shorthands.h

@@ -9,6 +9,7 @@
 
 namespace blink {
 
+struct NGCaretPosition;
 class LayoutBlockFlow;
 struct LocalCaretRect;
 
@@ -18,6 +19,8 @@ struct LocalCaretRect;
 
 const LayoutBlockFlow* NGInlineFormattingContextOf(const PositionInFlatTree&);
 
+NGCaretPosition ComputeNGCaretPosition(const PositionInFlatTreeWithAffinity&);
+
 LocalCaretRect ComputeNGLocalCaretRect(const PositionInFlatTreeWithAffinity&);
 
 bool InSameNGLineBox(const PositionInFlatTreeWithAffinity&,

third_party/blink/renderer/core/paint/ng/ng_paint_fragment_traversal.h

@@ -32,6 +32,10 @@ struct NGPaintFragmentTraversalContext {
   bool IsNull() const { return !parent; }
   const NGPaintFragment* GetFragment() const;
 
+  bool operator==(const NGPaintFragmentTraversalContext& other) const {
+    return parent == other.parent && index == other.index;
+  }
+
   const NGPaintFragment* parent = nullptr;
   unsigned index = 0;
 };