Add DocumentTiming metrics for "time to first text paint"

Source/platform/fonts/Font.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (c) 2007, 2008, 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 44 matching lines @@
 namespace blink {
 
 Font::Font()
 {
 }
 
 Font::Font(const FontDescription& fd)
     : m_fontDescription(fd)
     , m_canShapeWordByWord(0)
     , m_shapeWordByWordComputed(0)
+    , m_firstPaintReported(0)
 {
 }
 
 Font::Font(const Font& other)
     : m_fontDescription(other.m_fontDescription)
     , m_fontFallbackList(other.m_fontFallbackList)
     , m_canShapeWordByWord(0)
     , m_shapeWordByWordComputed(0)
+    , m_firstPaintReported(0)
 {
 }
 
 Font& Font::operator=(const Font& other)
 {
     m_fontDescription = other.m_fontDescription;
     m_fontFallbackList = other.m_fontFallbackList;
     m_canShapeWordByWord = other.m_canShapeWordByWord;
     m_shapeWordByWordComputed = other.m_shapeWordByWordComputed;
+    m_firstPaintReported = other.m_firstPaintReported;
     return *this;
 }
 
 bool Font::operator==(const Font& other) const
 {
     FontSelector* first = m_fontFallbackList ? m_fontFallbackList->fontSelector() : 0;
     FontSelector* second = other.m_fontFallbackList ? other.m_fontFallbackList->fontSelector() : 0;
 
     return first == second
         && m_fontDescription == other.m_fontDescription
@@ skipping 44 matching lines @@
     return width;
 }
 
 void Font::drawText(SkCanvas* canvas, const TextRunPaintInfo& runInfo,
     const FloatPoint& point, float deviceScaleFactor, const SkPaint& paint) const
 {
     // Don't draw anything while we are using custom fonts that are in the process of loading.
     if (shouldSkipDrawing())
         return;
 
+    reportFirstTextPaint();
+
     if (runInfo.cachedTextBlob && runInfo.cachedTextBlob->get()) {
         // we have a pre-cached blob -- happy joy!
         drawTextBlob(canvas, paint, runInfo.cachedTextBlob->get(), point.data());
         return;
     }
 
     GlyphBuffer glyphBuffer;
     buildGlyphBuffer(runInfo, glyphBuffer);
 
     drawGlyphBuffer(canvas, paint, runInfo, glyphBuffer, point, deviceScaleFactor);
 }
 
 void Font::drawBidiText(SkCanvas* canvas, const TextRunPaintInfo& runInfo, const FloatPoint& point, CustomFontNotReadyAction customFontNotReadyAction, float deviceScaleFactor, const SkPaint& paint) const
 {
     // Don't draw anything while we are using custom fonts that are in the process of loading,
     // except if the 'force' argument is set to true (in which case it will use a fallback
     // font).
     if (shouldSkipDrawing() && customFontNotReadyAction == DoNotPaintIfFontNotReady)
         return;
 
+    reportFirstTextPaint();
+
     // sub-run painting is not supported for Bidi text.
     const TextRun& run = runInfo.run;
     ASSERT((runInfo.from == 0) && (runInfo.to == run.length()));
     BidiResolver<TextRunIterator, BidiCharacterRun> bidiResolver;
     bidiResolver.setStatus(BidiStatus(run.direction(), run.directionalOverride()));
     bidiResolver.setPositionIgnoringNestedIsolates(TextRunIterator(&run, 0));
 
     // FIXME: This ownership should be reversed. We should pass BidiRunList
     // to BidiResolver in createBidiRunsForLine.
     BidiRunList<BidiCharacterRun>& bidiRuns = bidiResolver.runs();
@@ skipping 18 matching lines @@
         float runWidth = buildGlyphBuffer(subrunInfo, glyphBuffer);
         drawGlyphBuffer(canvas, paint, subrunInfo, glyphBuffer, currPoint, deviceScaleFactor);
 
         bidiRun = bidiRun->next();
         currPoint.move(runWidth, 0);
     }
 
     bidiRuns.deleteRuns();
 }
 
+void Font::reportFirstTextPaint() const
+{
+    if (m_firstPaintReported || !fontSelector())
+        return;
+    m_firstPaintReported = true;
+
+    if (m_fontFallbackList->hasCustomFont())
+        fontSelector()->reportFirstCustomFontText();
+    fontSelector()->reportFirstNonBlankText();
+}
+
 void Font::drawEmphasisMarks(SkCanvas* canvas, const TextRunPaintInfo& runInfo, const AtomicString& mark, const FloatPoint& point, float deviceScaleFactor, const SkPaint& paint) const
 {
     if (shouldSkipDrawing())
         return;
 
     FontCachePurgePreventer purgePreventer;
 
     GlyphData emphasisGlyphData;
     if (!getEmphasisMarkGlyphData(mark, emphasisGlyphData))
         return;
@@ skipping 607 matching lines @@
 {
     return m_fontFallbackList && m_fontFallbackList->loadingCustomFonts();
 }
 
 bool Font::isFallbackValid() const
 {
     return !m_fontFallbackList || m_fontFallbackList->isValid();
 }
 
 } // namespace blink