Fix the x-offset calculation when drawing the text.

ui/gfx/render_text_harfbuzz.cc

Index: ui/gfx/render_text_harfbuzz.cc
diff --git a/ui/gfx/render_text_harfbuzz.cc b/ui/gfx/render_text_harfbuzz.cc
index 7e916ff3ae21142a633c45521e402b3b1b44ebc8..f24732b7ff3f203bb9a300660c30b6b991ca0ba8 100644
--- a/ui/gfx/render_text_harfbuzz.cc
+++ b/ui/gfx/render_text_harfbuzz.cc
@@ -1012,8 +1012,10 @@ void RenderTextHarfBuzz::DrawVisualText(Canvas* canvas) {
                                    background_is_transparent());
       Range glyphs_range = run.CharRangeToGlyphRange(segment.char_range);
       scoped_ptr<SkPoint[]> positions(new SkPoint[glyphs_range.length()]);
-      SkScalar offset_x =
-          preceding_segment_widths - run.positions[glyphs_range.start()].x();
+      SkScalar offset_x = preceding_segment_widths -
+                          ((glyphs_range.GetMin() != 0)
+                               ? run.positions[glyphs_range.GetMin()].x()
+                               : 0);
       for (size_t j = 0; j < glyphs_range.length(); ++j) {
         positions[j] = run.positions[(glyphs_range.is_reversed()) ?
                                      (glyphs_range.start() - j) :