Add support for shaper-driven line breaking to HarfBuzzShaper

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.h

Index: third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.h
diff --git a/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.h b/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.h
index 7ef87d532ea518b19544ee564b7fd28d52fb967d..2d55fdb7caab4f7364940a6f344b85229d1ead54 100644
--- a/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.h
+++ b/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.h
@@ -42,7 +42,9 @@ namespace blink {
 class Font;
 class SimpleFontData;
 class HarfBuzzShaper;
+class LayoutUnit;
 struct HolesQueueItem;
+enum class LineBreakType;
 
 class PLATFORM_EXPORT HarfBuzzShaper final {
  public:
@@ -64,6 +66,17 @@ class PLATFORM_EXPORT HarfBuzzShaper final {
   // end offset equal to the length.
   PassRefPtr<ShapeResult> shape(const Font*, TextDirection) const;
 
+  // Shapes a line of text by finding a valid and appropriate break opportunity
+  // based on the shaping results for the entire paragraph.
+  // The output parameter breakOffset indicates the resulting break offset.
+  PassRefPtr<ShapeResult> shapeLine(const Font*,
+                                    const ShapeResult*,
+                                    unsigned startOffset,
+                                    const AtomicString locale,
+                                    LineBreakType,
+                                    LayoutUnit availableSpace,
+                                    unsigned* breakOffset) const;
+
   ~HarfBuzzShaper() {}
 
  private: