Route selection bounds updates through WebLayerTreeView

Source/core/rendering/compositing/CompositedSelectionBound.h

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@@ skipping 10 matching lines @@
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-#ifndef FontPlatformFeatures_h
-#define FontPlatformFeatures_h
+#ifndef CompositedSelectionBound_h
+#define CompositedSelectionBound_h
 
-#include "platform/PlatformExport.h"
+#include "platform/geometry/FloatPoint.h"
+#include "platform/graphics/GraphicsLayer.h"
 
 namespace blink {
 
-class FontPlatformFeatures {
-public:
-    static bool canReturnFallbackFontsForComplexText();
-    static bool canExpandAroundIdeographsInComplexText();
+struct CompositedSelectionBound {
+    enum Type {
+        Caret,
+        SelectionLeft,
+        SelectionRight
+    };
 
-private:
-    FontPlatformFeatures();
+    CompositedSelectionBound()
+        : type(Caret)
+        , layer(nullptr)
+    {
+    }
+
+    Type type;
+    GraphicsLayer* layer;
+    FloatPoint edgeTopInLayer;

[chrishtr, 2014/09/05 22:14:56]

Why isn't it just a rect?

[jdduke (slow), 2014/09/05 22:18:33]

We used a rect in the past, but abandoned it in favor of something more
explicit. The rect is convenient as far as data storage, but it's misleading
because 1) the edge always is one-dimensional in this case, and 2) the edge may
not be axis aligned. A line segment object would be ideal here, but I'm not sure
one exists currently?

[chrishtr, 2014/09/05 22:39:26]

Line segment doesn't exist.

What does edgeTop actually mean then? Is it referring to the vertical line of a
selection endpoint?

Why might it not be axis aligned to the graphics layer backing?

[jdduke (slow), 2014/09/05 23:30:45]

Yes.
You tell me :) If we're guaranteed that all types of text will always be axis
aligned relative to the the anchoring layer, then a rect would suffice. I wasn't
sure if that would always be the case, though I'm not also sure that it hurts to
be explicit that this is a one-dimensional edge.

[chrishtr, 2014/09/05 23:45:28]

I see. Then I suggest the names "edgeTop" and "edgeBottom", with a comment
saying that the line between these two points is the selection bound.
Text may not be axis-aligned to the containing graphics layer backing. e.g.
there may be a 2D transform on some text. Do you need to support this case?
If you do then the rect methods I referred to will not work. You'll have to map
the individual points from one coordinate space to the other.

+    FloatPoint edgeBottomInLayer;
 };
 
 } // namespace blink
 
 #endif