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

third_party/WebKit/Source/core/html/HTMLInputElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLInputElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLInputElement.cpp b/third_party/WebKit/Source/core/html/HTMLInputElement.cpp
index dd60325e359704461bc601ac3a7ba95e1048314c..6e8d6c2ce16580fe0c2fe21e314cf51bef4fe663 100644
--- a/third_party/WebKit/Source/core/html/HTMLInputElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLInputElement.cpp
@@ -67,6 +67,7 @@
 #include "core/html/forms/InputType.h"
 #include "core/html/forms/SearchInputType.h"
 #include "core/html/parser/HTMLParserIdioms.h"
+#include "core/html/shadow/ShadowElementNames.h"
 #include "core/layout/LayoutTheme.h"
 #include "core/page/ChromeClient.h"
 #include "platform/Language.h"
@@ -113,7 +114,7 @@ HTMLInputElement::HTMLInputElement(Document& document, HTMLFormElement* form, bo
     , m_parsingInProgress(createdByParser)
     , m_valueAttributeWasUpdatedAfterParsing(false)
     , m_canReceiveDroppedFiles(false)
-    , m_hasTouchEventHandler(false)
+    , m_hasPassiveTouchEventHandler(false)
     , m_shouldRevealPassword(false)
     , m_needsToUpdateViewValue(true)
     , m_isPlaceholderVisible(false)
@@ -405,18 +406,21 @@ void HTMLInputElement::updateTouchEventHandlerRegistry()
 {
     ASSERT(m_inputTypeView);
 
-    bool hasTouchEventHandler = m_inputTypeView->hasTouchEventHandler();
-    if (hasTouchEventHandler == !!m_hasTouchEventHandler)
+    bool hasPassiveTouchEventHandler = m_inputTypeView->hasPassiveTouchEventHandler();
+    if (hasPassiveTouchEventHandler == !!m_hasPassiveTouchEventHandler)
         return;
     // If the Document is being or has been stopped, don't register any handlers.
     if (document().frameHost() && document().lifecycle().state() < DocumentLifecycle::Stopping) {
         EventHandlerRegistry& registry = document().frameHost()->eventHandlerRegistry();
-        // TODO(dtapuska): Make this passive touch listener see crbug.com/584438
-        if (hasTouchEventHandler)
-            registry.didAddEventHandler(*this, EventHandlerRegistry::TouchStartOrMoveEventBlocking);
-        else
-            registry.didRemoveEventHandler(*this, EventHandlerRegistry::TouchStartOrMoveEventBlocking);
-        m_hasTouchEventHandler = hasTouchEventHandler;
+        if (hasPassiveTouchEventHandler) {
+            registry.didAddEventHandler(
+                *(this->userAgentShadowRoot()->getElementById(ShadowElementNames::sliderContainer())),

[majidvp, 2016/08/12 03:35:43]

This leaks lots of internal details of the RangeInputType to HTMLInputElement
and should be avoided.

I think, we really should get rid of this whole registration here and move the
registration inside SliderContainerElement itself.

HTMLInputElement should not be aware of existence of a touch handler and it
shouldn't need to update it. The touch handler gets registered when internal
shadow dom is created and de-registered when it is removed.


This involves a bit of work and may even be better suited as a follow up patch.
I suggest the following:

This patch 
------------ 
keep the logic here intact, i.e. register touch handler on input rather than
the slider container.

Follow up patch 
-------------- 
Register touch handler when constructing the SliderContainer and 
de-register when it is detached. This ensures the touch- action and touch 
handler are on the same element which is ideal. 

Also removes
InputTypeView::hasTouchEventHandler/m_hasPassiveTouchEventHandler/updateTouchEvent
HandlerRegister


Just my suggestion but please follow kent@ advice. He is the expert.

[tkent, 2016/08/12 06:15:18]

Yes, we shouldn't have inputtype-specific logic in HTMLInputElement.  At least,
we should introduce InputType::elementWithPassiveTouchEvent().

+                EventHandlerRegistry::TouchStartOrMoveEventPassive);
+        } else {
+            registry.didRemoveEventHandler(
+                *(this->userAgentShadowRoot()->getElementById(ShadowElementNames::sliderContainer())),
+                EventHandlerRegistry::TouchStartOrMoveEventPassive);
+        }
     }
 }
 
@@ -1161,7 +1165,7 @@ void HTMLInputElement::defaultEventHandler(Event* evt)
             return;
     }
 
-    if (evt->isTouchEvent() && m_inputTypeView->hasTouchEventHandler()) {
+    if (evt->isTouchEvent() && m_inputTypeView->hasPassiveTouchEventHandler()) {
         m_inputTypeView->handleTouchEvent(toTouchEvent(evt));
         if (evt->defaultHandled())
             return;
@@ -1514,7 +1518,7 @@ void HTMLInputElement::didMoveToNewDocument(Document& oldDocument)
 void HTMLInputElement::removeAllEventListeners()
 {
     HTMLTextFormControlElement::removeAllEventListeners();
-    m_hasTouchEventHandler = false;
+    m_hasPassiveTouchEventHandler = false;
 }
 
 bool HTMLInputElement::recalcWillValidate() const