Make a pen in eraser mode visible thru PointerEvent.buttons

The PointerEvent spec can't gracefully support a hovering pen in eraser
mode because a non-zero |buttons| field indicate an active buttons
state. The issue is currently being discussed in github:
  https://github.com/w3c/pointerevents/issues/134

Until the spec gets fixed, this CL exposes the eraser mode in a
spec-compliant way by hiding the eraser mode until the pen touches the
digitizer. Edge shows the same behavior.

This CL also adds X1, X2 & Eraser button/buttons values to
WebPointerProperties.

BUG=642455

Review-Url: https://codereview.chromium.org/2296303002
Cr-Commit-Position: refs/heads/master@{#416360}

components/test_runner/event_sender.cc

@@ -63,10 +63,11 @@ namespace test_runner {
 namespace {
 
 const int kRawMousePointerId = -1;
-const char* kPointerTypeStringUnknown = "";
-const char* kPointerTypeStringMouse = "mouse";
-const char* kPointerTypeStringPen = "pen";
-const char* kPointerTypeStringTouch = "touch";
+const char* const kPointerTypeStringUnknown = "";
+const char* const kPointerTypeStringMouse = "mouse";
+const char* const kPointerTypeStringTouch = "touch";
+const char* const kPointerTypeStringPen = "pen";
+const char* const kPointerTypeStringEraser = "eraser";
 
 // Assigns |pointerType| from the provided |args|. Returns false if there was
 // any error.
@@ -90,10 +91,12 @@ bool getPointerType(gin::Arguments* args,
     pointerType = WebMouseEvent::PointerType::Unknown;
   } else if (pointer_type_string == kPointerTypeStringMouse) {
     pointerType = WebMouseEvent::PointerType::Mouse;
-  } else if (pointer_type_string == kPointerTypeStringPen) {
-    pointerType = WebMouseEvent::PointerType::Pen;
   } else if (pointer_type_string == kPointerTypeStringTouch) {
     pointerType = WebMouseEvent::PointerType::Touch;
+  } else if (pointer_type_string == kPointerTypeStringPen) {
+    pointerType = WebMouseEvent::PointerType::Pen;
+  } else if (pointer_type_string == kPointerTypeStringEraser) {
+    pointerType = WebMouseEvent::PointerType::Eraser;
   } else {
     args->ThrowError();
     return false;
@@ -175,6 +178,10 @@ int GetWebMouseEventModifierForButton(WebMouseEvent::Button button) {
       return WebMouseEvent::MiddleButtonDown;
     case WebMouseEvent::Button::Right:
       return WebMouseEvent::RightButtonDown;
+    case WebPointerProperties::Button::X1:
+    case WebPointerProperties::Button::X2:
+    case WebPointerProperties::Button::Eraser:
+      return 0; // Not implemented yet
   }
   NOTREACHED();
   return 0;

third_party/WebKit/LayoutTests/fast/events/pointerevents/mouse-pointer-event-properties.html

@@ -20,6 +20,8 @@ description("Verifies that pointer event parameters are correct when fired throu
 
 var checkKeyModifiers = false;
 
+var inputPointerType = "";
+
 var pointerType = "";
 var penId = 0;
 var penPressure = 0;
@@ -54,6 +56,33 @@ var numericAttributes = [
     "height",
 ];
 
+function getExpectedNumericAttributeValueForPE(mouseEvent, attribute) {
+  var expectedValue = eval("mouseEvent." + attribute);
+
+  // Fix expectedValue for the cases where PE & ME differs
+  if (attribute == "button") {
+    if (mouseEvent.type != "mousedown" && mouseEvent.type != "mouseup")
+      expectedValue = -1;
+    else if (inputPointerType == "eraser")
+      expectedValue = 5;
+  } else if (attribute == "buttons") {
+    if (inputPointerType == "eraser" && mouseEvent.type == "mousedown")
+      expectedValue = 32;
+  } else if (attribute == "width" || attribute == "height") {
+    expectedValue = 1;
+  } else if (attribute == "pressure") {
+    if (pointerType == "mouse")
+      expectedValue = (mouseEvent.buttons == 0)? 0.0 : 0.5;
+    else
+      expectedValue = penPressure;
+  } else if (attribute == "tiltX") {
+    expectedValue = (pointerType == "mouse")? 0 : penTiltX;
+  } else if (attribute == "tiltY") {
+    expectedValue = (pointerType == "mouse")? 0 : penTiltY;
+  }
+  return expectedValue;
+}
+
 function init() {
   var targetDiv = document.getElementById("target");
 
@@ -89,24 +118,10 @@ function init() {
           shouldBeTrue("lastPointerEvents[0].isPrimary");
 
           numericAttributes.forEach(function(attribute) {
-            var expectedValue = eval("event." + attribute);
-            if (attribute == "button" && event.type != "mousedown" && event.type != "mouseup")
-              expectedValue = -1;
-            else if (attribute == "width" || attribute == "height")
-              expectedValue = 1;
-            else if (attribute == "pressure") {
-              if (pointerType == "mouse")
-                expectedValue = (event.buttons == 0)? 0.0 : 0.5;
-              else
-                expectedValue = penPressure;
-            }
-            else if (attribute == "tiltX")
-              expectedValue = (pointerType == "mouse")? 0 : penTiltX;
-            else if (attribute == "tiltY")
-              expectedValue = (pointerType == "mouse")? 0 : penTiltY;
-
+            var expectedValue = getExpectedNumericAttributeValueForPE(event, attribute);
             shouldBeEqualToNumber("lastPointerEvents[0]." + attribute, expectedValue);
           });
+
           shouldBeEqualToString("lastPointerEvents[0].view.name", "mainWindow");
 
         } else {
@@ -164,29 +179,30 @@ function runMouseTests(x, y) {
   debug("");
 }
 
-function runPenTests(x, y) {
-  debug("===== pen tests =====");
+function runPenTests(x, y, id, eraseMode) {
+  debug("===== pen tests " + (eraseMode? "(erase mode)" : "(draw mode)") + " =====");
   pointerType = "pen";
-  penId = 2;
+  inputPointerType = eraseMode? "eraser" : "pen";
+  penId = id;
   penPressure = 0.0;
   penTiltX = 0;
   penTiltY = 0;
 
   debug("--- move pen into target ---");
-  eventSender.mouseMoveTo(x + 5, y + 5, [], "pen", penId, penPressure, penTiltX, penTiltY);
+  eventSender.mouseMoveTo(x + 5, y + 5, [], inputPointerType, penId, penPressure, penTiltX, penTiltY);
   debug("");
 
   debug("--- move within target & tap ---");
   penTiltX = 45;
   penTiltY = -34;
-  eventSender.mouseMoveTo(x + 15, y + 15, [], "pen", penId, penPressure, penTiltX, penTiltY);
+  eventSender.mouseMoveTo(x + 15, y + 15, [], inputPointerType, penId, penPressure, penTiltX, penTiltY);
   penPressure = 0.75;
-  eventSender.mouseDown(0, [], "pen", penId, penPressure, penTiltX, penTiltY);
+  eventSender.mouseDown(0, [], inputPointerType, penId, penPressure, penTiltX, penTiltY);
   penPressure = 0.0;
-  eventSender.mouseUp(0, [], "pen", penId, penPressure, penTiltX, penTiltY);
+  eventSender.mouseUp(0, [], inputPointerType, penId, penPressure, penTiltX, penTiltY);
 
   debug("--- move pen out of target ---");
-  eventSender.mouseMoveTo(x - 5, y - 5, [], "pen", penId, penPressure, penTiltX, penTiltY);
+  eventSender.mouseMoveTo(x - 5, y - 5, [], inputPointerType, penId, penPressure, penTiltX, penTiltY);
 
   debug("");
 }
@@ -195,7 +211,8 @@ function runAllTests() {
   var rect = document.getElementById("target").getBoundingClientRect();
 
   runMouseTests(rect.left, rect.top);
-  runPenTests(rect.left, rect.top);
+  runPenTests(rect.left, rect.top, 2, false);
+  runPenTests(rect.left, rect.top, 3, true);
 }
 
 init();

third_party/WebKit/Source/core/events/MouseEvent.cpp

@@ -150,11 +150,11 @@ unsigned short MouseEvent::platformModifiersToButtons(unsigned modifiers)
     unsigned short buttons = 0;
 
     if (modifiers & PlatformEvent::LeftButtonDown)
-        buttons |= static_cast<unsigned short>(Buttons::Left);
+        buttons |= static_cast<unsigned short>(WebPointerProperties::Buttons::Left);
     if (modifiers & PlatformEvent::RightButtonDown)
-        buttons |= static_cast<unsigned short>(Buttons::Right);
+        buttons |= static_cast<unsigned short>(WebPointerProperties::Buttons::Right);
     if (modifiers & PlatformEvent::MiddleButtonDown)
-        buttons |= static_cast<unsigned short>(Buttons::Middle);
+        buttons |= static_cast<unsigned short>(WebPointerProperties::Buttons::Middle);
 
     return buttons;
 }

third_party/WebKit/Source/core/events/MouseEvent.h

@@ -92,13 +92,6 @@ public:
 
     EventDispatchMediator* createMediator() override;
 
-    enum class Buttons : unsigned {
-        None = 0,
-        Left = 1 << 0,
-        Right = 1 << 1,
-        Middle = 1 << 2
-    };
-
     DECLARE_VIRTUAL_TRACE();
 
 protected:

third_party/WebKit/Source/core/events/PointerEventFactory.cpp

@@ -22,8 +22,7 @@ const char* pointerTypeNameForWebPointPointerType(WebPointerProperties::PointerT
         return "touch";
     case WebPointerProperties::PointerType::Pen:
     case WebPointerProperties::PointerType::Eraser:
-        // TODO(mustaq): Continue eraser plumbing to web API.
-        // See crbug.com/642455
+        // TODO(mustaq): Fix when the spec starts supporting hovering erasers.
         return "pen";
     case WebPointerProperties::PointerType::Mouse:
         return "mouse";
@@ -57,16 +56,22 @@ const AtomicString& pointerEventNameForMouseEventName(
 
 unsigned short buttonToButtonsBitfield(WebPointerProperties::Button button)
 {
+#define CASE_BUTTON_TO_BUTTONS(enumLabel) \
+    case WebPointerProperties::Button::enumLabel:\
+        return static_cast<unsigned short>(WebPointerProperties::Buttons::enumLabel)
+
     switch (button) {
-    case WebPointerProperties::Button::NoButton:
-        return static_cast<unsigned short>(MouseEvent::Buttons::None);
-    case WebPointerProperties::Button::Left:
-        return static_cast<unsigned short>(MouseEvent::Buttons::Left);
-    case WebPointerProperties::Button::Right:
-        return static_cast<unsigned short>(MouseEvent::Buttons::Right);
-    case WebPointerProperties::Button::Middle:
-        return static_cast<unsigned short>(MouseEvent::Buttons::Middle);
+        CASE_BUTTON_TO_BUTTONS(NoButton);
+        CASE_BUTTON_TO_BUTTONS(Left);
+        CASE_BUTTON_TO_BUTTONS(Right);
+        CASE_BUTTON_TO_BUTTONS(Middle);
+        CASE_BUTTON_TO_BUTTONS(X1);
+        CASE_BUTTON_TO_BUTTONS(X2);
+        CASE_BUTTON_TO_BUTTONS(Eraser);
     }
+
+#undef CASE_BUTTON_TO_BUTTONS
+
     NOTREACHED();
     return 0;
 }
@@ -92,7 +97,15 @@ void PointerEventFactory::setIdTypeButtons(PointerEventInit& pointerEventInit,
     const IncomingId incomingId(pointerType, pointerProperties.id);
     int pointerId = addIdAndActiveButtons(incomingId, buttons != 0);
 
+    // Tweak the |buttons| to reflect pen eraser mode only if the pen is in
+    // active buttons state w/o even considering the eraser button.
+    // TODO(mustaq): Fix when the spec starts supporting hovering erasers.
+    if (pointerType == WebPointerProperties::PointerType::Eraser && buttons != 0) {
+        buttons |= static_cast<unsigned>(WebPointerProperties::Buttons::Eraser);
+        buttons &= ~static_cast<unsigned>(WebPointerProperties::Buttons::Left);
+    }
     pointerEventInit.setButtons(buttons);
+
     pointerEventInit.setPointerId(pointerId);
     pointerEventInit.setPointerType(pointerTypeNameForWebPointPointerType(pointerType));
     pointerEventInit.setIsPrimary(isPrimary(pointerId));
@@ -145,7 +158,12 @@ PointerEvent* PointerEventFactory::create(
 
     if (pointerEventName == EventTypeNames::pointerdown
         || pointerEventName == EventTypeNames::pointerup) {
-        pointerEventInit.setButton(static_cast<int>(mouseEvent.pointerProperties().button));
+        WebPointerProperties::Button button = mouseEvent.pointerProperties().button;
+        // TODO(mustaq): Fix when the spec starts supporting hovering erasers.
+        if (mouseEvent.pointerProperties().pointerType == WebPointerProperties::PointerType::Eraser
+            && button == WebPointerProperties::Button::Left)
+            button =  WebPointerProperties::Button::Eraser;
+        pointerEventInit.setButton(static_cast<int>(button));
     } else {
         DCHECK(pointerEventName == EventTypeNames::pointermove);
         pointerEventInit.setButton(static_cast<int>(WebPointerProperties::Button::NoButton));

third_party/WebKit/public/platform/WebPointerProperties.h

@@ -31,7 +31,20 @@ public:
         NoButton = -1,
         Left,
         Middle,
-        Right
+        Right,
+        X1,
+        X2,
+        Eraser
+    };
+
+    enum class Buttons : unsigned {
+        NoButton = 0,
+        Left = 1 << 0,
+        Right = 1 << 1,
+        Middle = 1 << 2,
+        X1 = 1 << 3,
+        X2 = 1 << 4,
+        Eraser = 1 << 5
     };
 
     enum class PointerType {