LayoutBox::scrollRectToVisible doesn't respect overflow:hidden property.

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

Index: third_party/WebKit/Source/core/layout/LayoutTextControlSingleLine.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTextControlSingleLine.cpp b/third_party/WebKit/Source/core/layout/LayoutTextControlSingleLine.cpp
index 32fbfe5c4488431415cf20f508d4e13f211addd5..f4433670313e5640d583d874aec161260712067b 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTextControlSingleLine.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTextControlSingleLine.cpp
@@ -351,16 +351,31 @@ LayoutUnit LayoutTextControlSingleLine::computeControlLogicalHeight(LayoutUnit l
     return lineHeight + nonContentHeight;
 }
 
-PassRefPtr<ComputedStyle> LayoutTextControlSingleLine::createInnerEditorStyle(const ComputedStyle& startStyle) const
+void LayoutTextControlSingleLine::addScrollbarPeudoStyle()

[ymalik, 2015/10/01 22:25:31]

Added this method for input fields that default to type="text" because an
invalid type was entered (e.g. type="foo").

I think it makes sense to have the scrollbar hiding logic for valid types in CSS
because doing it here causes additional repaint steps (noticed from failing
LayoutTests when only this function is used).

@skobes WDYT? 

[skobes, 2015/10/01 22:40:19]

It would be better to have this in one place instead of two different places. 
Can you clarify where the additional repaints come from?  I thought this would
all run during style recalc, before any painting occurs.

[ymalik, 2015/10/03 20:49:21]

Removed the logic from html.css

Discussed this in great details with you over email, but the reason for
repainting 
as you pointed out was because we were adding the style to the input element 
and not the inner editor. This caused a discrepancy between the style from 
StyleResolver and this method upon stylechange, marking the input as needs
repainting.

 {
+    if (!style()->hasPseudoStyle(SCROLLBAR)) {
+        RefPtr<ComputedStyle> noScrollbarStyle = ComputedStyle::create();
+        noScrollbarStyle->setStyleType(SCROLLBAR);
+        noScrollbarStyle->setDisplay(NONE);
+
+        mutableStyleRef().addCachedPseudoStyle(noScrollbarStyle);
+        mutableStyleRef().setHasPseudoStyle(SCROLLBAR);
+    }
+}
+
+PassRefPtr<ComputedStyle> LayoutTextControlSingleLine::createInnerEditorStyle(const ComputedStyle& startStyle)
+{
+    addScrollbarPeudoStyle();
     RefPtr<ComputedStyle> textBlockStyle = ComputedStyle::create();
     textBlockStyle->inheritFrom(startStyle);
     adjustInnerEditorStyle(*textBlockStyle);
 
     textBlockStyle->setWhiteSpace(PRE);
     textBlockStyle->setOverflowWrap(NormalOverflowWrap);
-    textBlockStyle->setOverflowX(OHIDDEN);
-    textBlockStyle->setOverflowY(OHIDDEN);
+    // Note that although overflowX/Y is set to scroll, the scrollbars will be
+    // hidden by the SCROLLBAR pseudo style added above.
+    textBlockStyle->setOverflowX(OSCROLL);
+    textBlockStyle->setOverflowY(OSCROLL);
     textBlockStyle->setTextOverflow(textShouldBeTruncated() ? TextOverflowEllipsis : TextOverflowClip);
 
     if (m_desiredInnerEditorLogicalHeight >= 0)