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

third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp

Index: third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp b/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
index 3e86c47489d9828fad5e5956afdf62d54b6a2fdb..2a7a70605d4cb59019b8c918cb6545c7daafccb6 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
@@ -1445,6 +1445,7 @@ template <CSSPropertyPriority priority>
 void StyleResolver::applyProperties(StyleResolverState& state, const StylePropertySet* properties, bool isImportant, bool inheritedOnly, PropertyWhitelistType propertyWhitelistType)
 {
     unsigned propertyCount = properties->propertyCount();
+    bool hasTouchAction = false;
     for (unsigned i = 0; i < propertyCount; ++i) {
         StylePropertySet::PropertyReference current = properties->propertyAt(i);
         CSSPropertyID property = current.id();
@@ -1476,7 +1477,20 @@ void StyleResolver::applyProperties(StyleResolverState& state, const StyleProper
         if (!CSSPropertyPriorityData<priority>::propertyHasPriority(property))
             continue;
 
+        if (property == CSSPropertyTouchAction) {
+            hasTouchAction = true;
+        }
+
         StyleBuilder::applyProperty(current.id(), state, current.value());
+
+        if (property == CSSPropertyWebkitAppearance && !hasTouchAction) {

[tkent, 2016/08/09 00:29:46]

This code looks like the state.style() will have touch-action:pan-* even if the
element is not <input type=range>.

We have appearance-specific style adjustment code in LayoutTheme::adjustStyle().
We can check <input type=range> inside it.
Also, we have some other slider appearances; MediaFullScreenVolumeSliderPart,
MediaSliderPart, and MediaVolumeSliderPart.

+            if (state.style()->appearance() == SliderVerticalPart) {
+                state.style()->setTouchAction(TouchActionPanX);
+            }
+            if (state.style()->appearance() == SliderHorizontalPart) {
+                state.style()->setTouchAction(TouchActionPanY);
+            }
+        }
     }
 }