Remove the blocking touch handlers for the input[type=range] and add touch-action instead

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

Index: third_party/WebKit/Source/core/layout/LayoutTheme.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTheme.cpp b/third_party/WebKit/Source/core/layout/LayoutTheme.cpp
index 6d830002df66fcebd3c01e77bd2c49bf04eef9ba..5884865229f137cbc7f3d60396cf9a44cbae5d65 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTheme.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTheme.cpp
@@ -210,6 +210,14 @@ void LayoutTheme::adjustStyle(ComputedStyle& style, Element* e)
         return adjustMenuListStyle(style, e);
     case MenulistButtonPart:
         return adjustMenuListButtonStyle(style, e);
+    case SliderVerticalPart:
+    case SliderHorizontalPart:
+    case MediaFullScreenVolumeSliderPart:
+    case MediaSliderPart:
+    case MediaVolumeSliderPart:
+        if (e->tagName() != "INPUT" || e->getAttribute("type") != "range")
+            return;

[majidvp, 2016/08/09 18:30:09]

Better to move this inside adjustSliderStyle.
Also better tests are: 

isHTMLInputElement()
and
element->type() != InputTypeNames::range

+        return adjustSliderStyle(style);
     case SliderThumbHorizontalPart:
     case SliderThumbVerticalPart:
         return adjustSliderThumbStyle(style);
@@ -627,6 +635,19 @@ void LayoutTheme::adjustMenuListButtonStyle(ComputedStyle&, Element*) const
 {
 }
 
+void LayoutTheme::adjustSliderStyle(ComputedStyle& style) const
+{
+    if (style.getTouchAction() != TouchActionAuto) {

[majidvp, 2016/08/09 18:30:09]

why do you need this? 
Is this to prevent overriding author's styling?

It is odd that you need this. Some points:

1. Should authors actually be able to modify the style for this user agent 
   created in shadow dom? I would say no in general. They can always
   do it in devtools but if they do we can just rely on CSS resolution to pick
   the effective value.

2. touch-action walks up the chain and combines all ancestor touch-actions
    so if there is a need, authors can actually update the shadow host style
    to control the touch action and don't need to reach inside the shadow
    dom tree.
 

+        return;
+    }
+    if (style.appearance() == SliderVerticalPart) {
+        style.setTouchAction(TouchActionPanX);
+    } else {
+        style.setTouchAction(TouchActionPanY);
+    }
+    return;

[majidvp, 2016/08/09 18:30:09]

This return is unnecessary.

+}
+
 void LayoutTheme::adjustSliderThumbStyle(ComputedStyle& style) const
 {
     adjustSliderThumbSize(style);