Fix not autosizing ruby elements issue.

third_party/WebKit/Source/core/layout/LayoutText.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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 1370 matching lines @@
   const SimpleFontData* fontData = f.primaryFont();
   DCHECK(fontData);
 
   GlyphOverflow glyphOverflow;
   if (fontData) {
     glyphOverflow.setFromBounds(
         glyphBounds, fontData->getFontMetrics().floatAscent(),
         fontData->getFontMetrics().floatDescent(), m_maxWidth);
   }
   // We shouldn't change our mind once we "know".
-  ASSERT(!m_knownToHaveNoOverflowAndNoFallbackFonts ||
-         (fallbackFonts.isEmpty() && glyphOverflow.isApproximatelyZero()));
+  if (!preferredLogicalWidthsDirty()) {

[pdr., 2017/02/10 04:10:46]

I think this dcheck should still work. Do you know why it needs the prefWidths
check?

[cathiechentx, 2017/02/10 05:17:47]

Hesitated to make this change too. The reason to fail this dcheck is:

1. After the first pass of layout, m_knownToHaveNoOverflowAndNoFallbackFonts is
true. Resized. Triggle layout.

2. Layout ruby. When autosize ruby, we changed ruby's inner layouttext's style
by setStyleInternal() in applyMultiplier(). setStyleInternal() won't change the
state of m_knownToHaveNoOverflowAndNoFallbackFonts. So
m_knownToHaveNoOverflowAndNoFallbackFonts remains true.

3. Layout rubyRun, rubyRun needs recalculate prefWidth. So it comes to here with
"m_knownToHaveNoOverflowAndNoFallbackFonts==true".

Maybe we could set m_knownToHaveNoOverflowAndNoFallbackFonts to false after we
changed the style of layouttext by setStyleInternal()?

[pdr., 2017/02/10 19:27:09]

Can you add a test for this? Just naively removing the conditional doesn't make
any tests hit this assert, but I see what you mean about how it can be hit.

If this dcheck is firing, is it because we have glyphOverflow when we didn't
before? I wonder if we need to force the entire ruby run to be recalculated
(maybe using setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation instead
of setNeedsLayoutAndFullPaintInvalidation)?

[cathiechentx, 2017/02/13 14:53:56]

fallbackFonts is not empty...

[cathiechentx, 2017/02/15 14:19:20]

Update:)

Actuall fallbackFonts is empty.

"If this dcheck is firing, is it because we have glyphOverflow when we didn't
before?"
Yes! The glyphOverflow of some font-family is different when font-size is
changed.

Analysis:
The below is the log of glyphOverflow printing before that 'DCHECK'.
They are the glyphOverflow of 'n' with 'font-family:Times New Roman;' and
font-size from 12px to 30px.
They are printed in SumSung Glaxy S4.
As we can see glyphOverflow is different when font-size is changed.
As a result of autosize the font-size could be changed when screen rotated.
It could change from glyphOverflow.isApproximatelyZero==true to
glyphOverflow.isApproximatelyZero==false.
So m_knownToHaveNoOverflowAndNoFallbackFonts could change from true to false
after screen rotated.
The test case 'ResizeAndGlyphOverflowChanged' could reproduce this issue.

Solution:
I think its reasonable to set 'm_knownToHaveNoOverflowAndNoFallbackFonts' false
of layoutText after this layoutText's computeSize is changed in
applyMultiplier() by setStyleInternal().
We do not know if there any change of glyphOverflow.

Log:
glyphOverflow=(0.000000, 0.259766, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.614746, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.324707, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.034668, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.389648, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.099609, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.164551, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.229492, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)
glyphOverflow=(0.000000, 0.000000, 0.000000, 0.000000)

+    DCHECK(!m_knownToHaveNoOverflowAndNoFallbackFonts ||
+           (fallbackFonts.isEmpty() && glyphOverflow.isApproximatelyZero()));
+  }
   m_knownToHaveNoOverflowAndNoFallbackFonts =
       fallbackFonts.isEmpty() && glyphOverflow.isApproximatelyZero();
 
   clearPreferredLogicalWidthsDirty();
 }
 
 bool LayoutText::isAllCollapsibleWhitespace() const {
   unsigned length = textLength();
   if (is8Bit()) {
     for (unsigned i = 0; i < length; ++i) {
@@ skipping 606 matching lines @@
   LayoutRect rect = LayoutRect(
       IntRect(firstRunX(), firstRunY(), linesBox.width(), linesBox.height()));
   LayoutBlock* block = containingBlock();
   if (block && hasTextBoxes())
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink