Track the region where text is painted.

Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp

Index: Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp
diff --git a/Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp b/Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp
index 513c8d9c58e27b5dbfbc63d9b7b52016394e6fdb..1e7fbb16ffb79b67b3636a3cf32464549160cfe8 100644
--- a/Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp
+++ b/Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp
@@ -61,7 +61,7 @@ bool Font::canExpandAroundIdeographsInComplexText()
 
 void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
                       const GlyphBuffer& glyphBuffer,  int from, int numGlyphs,
-                      const FloatPoint& point) const {
+                      const FloatPoint& point, const FloatRect& textRect) const {
     SkASSERT(sizeof(GlyphBufferGlyph) == sizeof(uint16_t)); // compile-time assert
 
     const GlyphBufferGlyph* glyphs = glyphBuffer.glyphs(from);
@@ -109,10 +109,10 @@ void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
                 path.reset();
                 path.moveTo(vPosBegin[i]);
                 path.lineTo(vPosEnd[i]);
-                platformContext->drawTextOnPath(glyphs + i, 2, path, 0, paint);
+                platformContext->drawTextOnPath(glyphs + i, 2, path, textRect, 0, paint);
             }
         } else
-            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, paint);
+            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, textRect, paint);
     }
 
     if ((textMode & TextModeStroke)
@@ -138,10 +138,10 @@ void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
                 path.reset();
                 path.moveTo(vPosBegin[i]);
                 path.lineTo(vPosEnd[i]);
-                platformContext->drawTextOnPath(glyphs + i, 2, path, 0, paint);
+                platformContext->drawTextOnPath(glyphs + i, 2, path, textRect, 0, paint);
             }
         } else
-            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, paint);
+            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, textRect, paint);
     }
 }
 
@@ -152,7 +152,8 @@ static void setupForTextPainting(SkPaint* paint, SkColor color)
 }
 
 void Font::drawComplexText(GraphicsContext* gc, const TextRun& run,
-                           const FloatPoint& point, int from, int to) const
+                           const FloatPoint& point, const FloatRect& textRect,
+                           int from, int to) const
 {
     if (!run.length())
         return;
@@ -182,10 +183,10 @@ void Font::drawComplexText(GraphicsContext* gc, const TextRun& run,
     if (!shaper.shape(&glyphBuffer))
         return;
     FloatPoint adjustedPoint = shaper.adjustStartPoint(point);
-    drawGlyphBuffer(gc, run, glyphBuffer, adjustedPoint);
+    drawGlyphBuffer(gc, run, glyphBuffer, adjustedPoint, textRect);
 }
 
-void Font::drawEmphasisMarksForComplexText(GraphicsContext* /* context */, const TextRun& /* run */, const AtomicString& /* mark */, const FloatPoint& /* point */, int /* from */, int /* to */) const
+void Font::drawEmphasisMarksForComplexText(GraphicsContext* /* context */, const TextRun& /* run */, const AtomicString& /* mark */, const FloatPoint& /* point */, const FloatRect& /* textRect */, int /* from */, int /* to */) const
 {
     notImplemented();
 }