RenderText: Don't default-construct gfx::Fonts unnecessarily

ui/gfx/render_text_mac.mm

Index: ui/gfx/render_text_mac.mm
diff --git a/ui/gfx/render_text_mac.mm b/ui/gfx/render_text_mac.mm
index 915f51f927a75e665124221256000cce10843102..5a4e5b115b99aa6f1033438e549d602e954e9a76 100644
--- a/ui/gfx/render_text_mac.mm
+++ b/ui/gfx/render_text_mac.mm
@@ -118,7 +118,8 @@ std::vector<RenderText::FontSpan> RenderTextMac::GetFontSpansForTesting() {
   for (size_t i = 0; i < runs_.size(); ++i) {
     const CFRange cf_range = CTRunGetStringRange(runs_[i].ct_run);
     const Range range(cf_range.location, cf_range.location + cf_range.length);
-    spans.push_back(RenderText::FontSpan(runs_[i].font, range));
+    spans.push_back(RenderText::FontSpan(
+        gfx::Font(base::mac::CFToNSCast(runs_[i].ct_font.get())), range));
   }
 
   return spans;
@@ -210,9 +211,7 @@ void RenderTextMac::DrawVisualText(internal::SkiaTextRenderer* renderer) {
   for (size_t i = 0; i < runs_.size(); ++i) {
     const TextRun& run = runs_[i];
     renderer->SetForegroundColor(run.foreground);
-
-    CTFontRef ct_font = static_cast<CTFontRef>(run.font.GetNativeFont());
-    renderer->SetTextSize(CTFontGetSize(ct_font));
+    renderer->SetTextSize(CTFontGetSize(run.ct_font));
 
     // The painter adds its own ref. So don't |release()| it from the ref ptr in
     // TextRun.
@@ -236,7 +235,7 @@ RenderTextMac::TextRun::TextRun()
       strike(false),
       diagonal_strike(false) {}
 
-RenderTextMac::TextRun::TextRun(const TextRun& other) = default;
+RenderTextMac::TextRun::TextRun(TextRun&& other) = default;
 
 RenderTextMac::TextRun::~TextRun() {}
 
@@ -379,7 +378,7 @@ void RenderTextMac::ComputeRuns() {
       continue;
     }
 
-    runs_.push_back(TextRun());
+    runs_.emplace_back();
     TextRun* run = &runs_.back();
     run->ct_run = ct_run;
     run->origin = run_origin;
@@ -414,7 +413,7 @@ void RenderTextMac::ComputeRuns() {
     CFDictionaryRef attributes = CTRunGetAttributes(ct_run);
     CTFontRef ct_font = base::mac::GetValueFromDictionary<CTFontRef>(
         attributes, kCTFontAttributeName);
-    run->font = Font(static_cast<NSFont*>(ct_font));
+    run->ct_font.reset(ct_font, base::scoped_policy::RETAIN);
     run->typeface.reset(SkCreateTypefaceFromCTFont(ct_font));
 
     const CGColorRef foreground = base::mac::GetValueFromDictionary<CGColorRef>(