Fix missing fields in GestureScrollBegin/Update/End event conversions.

Some of the fields were missing from the event conversion path that
occurs when a plugin is used. This caused fields to be populated
with the default value. As a result the default values enabled
overscroll scrolling when using a low precision delta
mouse wheel with an MacOSX machine.

The bug did not indicate which precision of mouse was being
used but overscrolling for PDF files with a touchpad or a magic
mouse (which have high precision deltas) still enable
elastic overscroll; but that is consistent with MacOSX.
This is a behavioural change for MacOSX but is consistent
with Safari when using a high precision mouse.

BUG=596778

Review URL: https://codereview.chromium.org/1829743003

Cr-Commit-Position: refs/heads/master@{#382901}

5 files changed, 162 insertions, 27 deletions

diff --git a/third_party/WebKit/Source/core/events/GestureEvent.cpp b/third_party/WebKit/Source/core/events/GestureEvent.cpp
index f758af2..97575e9 100644
--- a/third_party/WebKit/Source/core/events/GestureEvent.cpp
+++ b/third_party/WebKit/Source/core/events/GestureEvent.cpp
@@ -38,6 +38,8 @@ PassRefPtrWillBeRawPtr<GestureEvent> GestureEvent::create(PassRefPtrWillBeRawPtr
     float velocityX = 0;
     float velocityY = 0;
     bool inertial = false;
+    bool synthetic = false;
+    ScrollGranularity deltaUnits = ScrollGranularity::ScrollByPrecisePixel;
 
     GestureSource source = GestureSourceUninitialized;
     switch (event.source()) {
@@ -53,9 +55,17 @@ PassRefPtrWillBeRawPtr<GestureEvent> GestureEvent::create(PassRefPtrWillBeRawPtr
 
     switch (event.type()) {
     case PlatformEvent::GestureScrollBegin:
-        eventType = EventTypeNames::gesturescrollstart; break;
+        eventType = EventTypeNames::gesturescrollstart;
+        synthetic = event.synthetic();
+        deltaUnits = event.deltaUnits();
+        inertial = event.inertial();
+        break;
     case PlatformEvent::GestureScrollEnd:
-        eventType = EventTypeNames::gesturescrollend; break;
+        eventType = EventTypeNames::gesturescrollend;
+        synthetic = event.synthetic();
+        deltaUnits = event.deltaUnits();
+        inertial = event.inertial();
+        break;
     case PlatformEvent::GestureScrollUpdate:
         // Only deltaX/Y are used when converting this
         // back to a PlatformGestureEvent.
@@ -63,6 +73,7 @@ PassRefPtrWillBeRawPtr<GestureEvent> GestureEvent::create(PassRefPtrWillBeRawPtr
         deltaX = event.deltaX();
         deltaY = event.deltaY();
         inertial = event.inertial();
+        deltaUnits = event.deltaUnits();
         break;
     case PlatformEvent::GestureTap:
         eventType = EventTypeNames::gesturetap; break;
@@ -87,7 +98,7 @@ PassRefPtrWillBeRawPtr<GestureEvent> GestureEvent::create(PassRefPtrWillBeRawPtr
     default:
         return nullptr;
     }
-    return adoptRefWillBeNoop(new GestureEvent(eventType, view, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(), event.getModifiers(), deltaX, deltaY, velocityX, velocityY, inertial, event.timestamp(), event.resendingPluginId(), source));
+    return adoptRefWillBeNoop(new GestureEvent(eventType, view, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(), event.getModifiers(), deltaX, deltaY, velocityX, velocityY, inertial, synthetic, deltaUnits, event.timestamp(), event.resendingPluginId(), source));
 }
 
 const AtomicString& GestureEvent::interfaceName() const
@@ -109,18 +120,22 @@ GestureEvent::GestureEvent()
     , m_velocityX(0)
     , m_velocityY(0)
     , m_inertial(false)
+    , m_synthetic(false)
+    , m_deltaUnits(ScrollGranularity::ScrollByPrecisePixel)
     , m_source(GestureSourceUninitialized)
     , m_resendingPluginId(-1)
 {
 }
 
-GestureEvent::GestureEvent(const AtomicString& type, PassRefPtrWillBeRawPtr<AbstractView> view, int screenX, int screenY, int clientX, int clientY, PlatformEvent::Modifiers modifiers, float deltaX, float deltaY, float velocityX, float velocityY, bool inertial, double platformTimeStamp, int resendingPluginId, GestureSource source)
+GestureEvent::GestureEvent(const AtomicString& type, PassRefPtrWillBeRawPtr<AbstractView> view, int screenX, int screenY, int clientX, int clientY, PlatformEvent::Modifiers modifiers, float deltaX, float deltaY, float velocityX, float velocityY, bool inertial, bool synthetic, ScrollGranularity deltaUnits, double platformTimeStamp, int resendingPluginId, GestureSource source)
     : MouseRelatedEvent(type, true, true, nullptr, view, 0, IntPoint(screenX, screenY), IntPoint(clientX, clientY), IntPoint(0, 0), modifiers, platformTimeStamp, PositionType::Position)
     , m_deltaX(deltaX)
     , m_deltaY(deltaY)
     , m_velocityX(velocityX)
     , m_velocityY(velocityY)
     , m_inertial(inertial)
+    , m_synthetic(synthetic)
+    , m_deltaUnits(deltaUnits)
     , m_source(source)
     , m_resendingPluginId(resendingPluginId)
 {
diff --git a/third_party/WebKit/Source/core/events/GestureEvent.h b/third_party/WebKit/Source/core/events/GestureEvent.h
index 0f8c06c..46ea208 100644
--- a/third_party/WebKit/Source/core/events/GestureEvent.h
+++ b/third_party/WebKit/Source/core/events/GestureEvent.h
@@ -57,19 +57,22 @@ public:
 
     GestureSource source() const { return m_source; }
     int resendingPluginId() const { return m_resendingPluginId; }
+    bool synthetic() const { return m_synthetic; }
+    ScrollGranularity deltaUnits() const { return m_deltaUnits; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     GestureEvent();
-    GestureEvent(const AtomicString& type, PassRefPtrWillBeRawPtr<AbstractView>, int screenX, int screenY, int clientX, int clientY, PlatformEvent::Modifiers, float deltaX, float deltaY, float velocityX, float velocityY, bool inertial, double platformTimeStamp, int resendingPluginId, GestureSource);
+    GestureEvent(const AtomicString& type, PassRefPtrWillBeRawPtr<AbstractView>, int screenX, int screenY, int clientX, int clientY, PlatformEvent::Modifiers, float deltaX, float deltaY, float velocityX, float velocityY, bool inertial, bool synthetic, ScrollGranularity deltaUnits, double platformTimeStamp, int resendingPluginId, GestureSource);
 
     float m_deltaX;
     float m_deltaY;
     float m_velocityX;
     float m_velocityY;
     bool m_inertial;
-
+    bool m_synthetic;
+    ScrollGranularity m_deltaUnits;
     GestureSource m_source;
     int m_resendingPluginId;
 };
diff --git a/third_party/WebKit/Source/platform/PlatformGestureEvent.h b/third_party/WebKit/Source/platform/PlatformGestureEvent.h
index 350fe9e..86ec241 100644
--- a/third_party/WebKit/Source/platform/PlatformGestureEvent.h
+++ b/third_party/WebKit/Source/platform/PlatformGestureEvent.h
@@ -99,19 +99,19 @@ public:
 
     float deltaX() const
     {
-        ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
+        ASSERT(m_type == PlatformEvent::GestureScrollBegin || m_type == PlatformEvent::GestureScrollUpdate);
         return m_data.m_scroll.m_deltaX;
     }
 
     float deltaY() const
     {
-        ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
+        ASSERT(m_type == PlatformEvent::GestureScrollBegin || m_type == PlatformEvent::GestureScrollUpdate);
         return m_data.m_scroll.m_deltaY;
     }
 
     ScrollGranularity deltaUnits() const
     {
-        ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
+        ASSERT(m_type == PlatformEvent::GestureScrollBegin || m_type == PlatformEvent::GestureScrollUpdate || m_type == PlatformEvent::GestureScrollEnd);
         return m_data.m_scroll.m_deltaUnits;
     }
 
@@ -135,10 +135,16 @@ public:
 
     bool inertial() const
     {
-        ASSERT(m_type == PlatformEvent::GestureScrollUpdate || m_type == PlatformEvent::GestureScrollEnd);
+        ASSERT(m_type == PlatformEvent::GestureScrollBegin || m_type == PlatformEvent::GestureScrollUpdate || m_type == PlatformEvent::GestureScrollEnd);
         return m_data.m_scroll.m_inertial;
     }
 
+    bool synthetic() const
+    {
+        ASSERT(m_type == PlatformEvent::GestureScrollBegin || m_type == PlatformEvent::GestureScrollEnd);
+        return m_data.m_scroll.m_synthetic;
+    }
+
     int resendingPluginId() const
     {
         if (m_type == PlatformEvent::GestureScrollUpdate
@@ -214,6 +220,8 @@ protected:
         } m_tap;
 
         struct {
+            // |m_deltaX| and |m_deltaY| represent deltas in GSU but
+            // are only hints in GSB.
             float m_deltaX;
             float m_deltaY;
             float m_velocityX;
@@ -222,6 +230,7 @@ protected:
             bool m_inertial;
             ScrollGranularity m_deltaUnits;
             int m_resendingPluginId;
+            bool m_synthetic;
         } m_scroll;
 
         struct {
diff --git a/third_party/WebKit/Source/web/WebInputEventConversion.cpp b/third_party/WebKit/Source/web/WebInputEventConversion.cpp
index 946fd9d..58d1c02 100644
--- a/third_party/WebKit/Source/web/WebInputEventConversion.cpp
+++ b/third_party/WebKit/Source/web/WebInputEventConversion.cpp
@@ -49,7 +49,8 @@
 
 namespace blink {
 
-static float scaleDeltaToWindow(const Widget* widget, float delta)
+namespace {
+float scaleDeltaToWindow(const Widget* widget, float delta)
 {
     float scale = 1;
     if (widget) {
@@ -60,7 +61,7 @@ static float scaleDeltaToWindow(const Widget* widget, float delta)
     return delta / scale;
 }
 
-static FloatSize scaleSizeToWindow(const Widget* widget, FloatSize size)
+FloatSize scaleSizeToWindow(const Widget* widget, FloatSize size)
 {
     return FloatSize(scaleDeltaToWindow(widget, size.width()), scaleDeltaToWindow(widget, size.height()));
 }
@@ -70,7 +71,7 @@ static FloatSize scaleSizeToWindow(const Widget* widget, FloatSize size)
 // in the root layer (see updateRootLayerTransform in WebViewImpl) as well as the overscroll effect on OSX.
 // This is in addition to the visual viewport "pinch-zoom" transformation and is one of the few cases where
 // the visual viewport is not equal to the renderer's coordinate-space.
-static FloatPoint convertHitPointToRootFrame(const Widget* widget, FloatPoint pointInRendererViewport)
+FloatPoint convertHitPointToRootFrame(const Widget* widget, FloatPoint pointInRendererViewport)
 {
     float scale = 1;
     IntSize offset;
@@ -90,7 +91,7 @@ static FloatPoint convertHitPointToRootFrame(const Widget* widget, FloatPoint po
         (pointInRendererViewport.y() - offset.height()) / scale + visualViewport.y() + overscrollOffset.height());
 }
 
-static unsigned toPlatformModifierFrom(WebMouseEvent::Button button)
+unsigned toPlatformModifierFrom(WebMouseEvent::Button button)
 {
     if (button == WebMouseEvent::ButtonNone)
         return 0;
@@ -104,6 +105,38 @@ static unsigned toPlatformModifierFrom(WebMouseEvent::Button button)
     return webMouseButtonToPlatformModifier[button];
 }
 
+ScrollGranularity toPlatformScrollGranularity(WebGestureEvent::ScrollUnits units)
+{
+    switch (units) {
+    case WebGestureEvent::ScrollUnits::PrecisePixels:
+        return ScrollGranularity::ScrollByPrecisePixel;
+    case WebGestureEvent::ScrollUnits::Pixels:
+        return ScrollGranularity::ScrollByPixel;
+    case WebGestureEvent::ScrollUnits::Page:
+        return ScrollGranularity::ScrollByPage;
+    default:
+        ASSERT_NOT_REACHED();
+        return ScrollGranularity::ScrollByPrecisePixel;
+    }
+}
+
+WebGestureEvent::ScrollUnits toWebGestureScrollUnits(ScrollGranularity granularity)
+{
+    switch (granularity) {
+    case ScrollGranularity::ScrollByPrecisePixel:
+        return WebGestureEvent::ScrollUnits::PrecisePixels;
+    case ScrollGranularity::ScrollByPixel:
+        return WebGestureEvent::ScrollUnits::Pixels;
+    case ScrollGranularity::ScrollByPage:
+        return WebGestureEvent::ScrollUnits::Page;
+    default:
+        ASSERT_NOT_REACHED();
+        return WebGestureEvent::ScrollUnits::PrecisePixels;
+    }
+}
+
+} // namespace
+
 // MakePlatformMouseEvent -----------------------------------------------------
 
 // TODO(mustaq): Add tests for this.
@@ -185,10 +218,18 @@ PlatformGestureEventBuilder::PlatformGestureEventBuilder(Widget* widget, const W
     case WebInputEvent::GestureScrollBegin:
         m_type = PlatformEvent::GestureScrollBegin;
         m_data.m_scroll.m_resendingPluginId = e.resendingPluginId;
+        m_data.m_scroll.m_deltaX = e.data.scrollBegin.deltaXHint;
+        m_data.m_scroll.m_deltaY = e.data.scrollBegin.deltaYHint;
+        m_data.m_scroll.m_deltaUnits = toPlatformScrollGranularity(e.data.scrollBegin.deltaHintUnits);
+        m_data.m_scroll.m_inertial = e.data.scrollBegin.inertial;
+        m_data.m_scroll.m_synthetic = e.data.scrollBegin.synthetic;
         break;
     case WebInputEvent::GestureScrollEnd:
         m_type = PlatformEvent::GestureScrollEnd;
         m_data.m_scroll.m_resendingPluginId = e.resendingPluginId;
+        m_data.m_scroll.m_deltaUnits = toPlatformScrollGranularity(e.data.scrollEnd.deltaUnits);
+        m_data.m_scroll.m_inertial = e.data.scrollEnd.inertial;
+        m_data.m_scroll.m_synthetic = e.data.scrollEnd.synthetic;
         break;
     case WebInputEvent::GestureFlingStart:
         m_type = PlatformEvent::GestureFlingStart;
@@ -204,19 +245,7 @@ PlatformGestureEventBuilder::PlatformGestureEventBuilder(Widget* widget, const W
         m_data.m_scroll.m_velocityY = e.data.scrollUpdate.velocityY;
         m_data.m_scroll.m_preventPropagation = e.data.scrollUpdate.preventPropagation;
         m_data.m_scroll.m_inertial = e.data.scrollUpdate.inertial;
-        switch (e.data.scrollUpdate.deltaUnits) {
-        case WebGestureEvent::ScrollUnits::PrecisePixels:
-            m_data.m_scroll.m_deltaUnits = ScrollGranularity::ScrollByPrecisePixel;
-            break;
-        case WebGestureEvent::ScrollUnits::Pixels:
-            m_data.m_scroll.m_deltaUnits = ScrollGranularity::ScrollByPixel;
-            break;
-        case WebGestureEvent::ScrollUnits::Page:
-            m_data.m_scroll.m_deltaUnits = ScrollGranularity::ScrollByPage;
-            break;
-        default:
-            ASSERT_NOT_REACHED();
-        }
+        m_data.m_scroll.m_deltaUnits = toPlatformScrollGranularity(e.data.scrollUpdate.deltaUnits);
         break;
     case WebInputEvent::GestureTap:
         m_type = PlatformEvent::GestureTap;
@@ -712,11 +741,20 @@ WebGestureEventBuilder::WebGestureEventBuilder(const LayoutObject* layoutObject,
     } else if (event.type() == EventTypeNames::gesturescrollstart) {
         type = GestureScrollBegin;
         resendingPluginId = event.resendingPluginId();
+        data.scrollBegin.deltaXHint = event.deltaX();
+        data.scrollBegin.deltaYHint = event.deltaY();
+        data.scrollBegin.deltaHintUnits = toWebGestureScrollUnits(event.deltaUnits());
+        data.scrollBegin.inertial = event.inertial();
+        data.scrollBegin.synthetic = event.synthetic();
     } else if (event.type() == EventTypeNames::gesturescrollend) {
         type = GestureScrollEnd;
         resendingPluginId = event.resendingPluginId();
+        data.scrollEnd.deltaUnits = toWebGestureScrollUnits(event.deltaUnits());
+        data.scrollEnd.inertial = event.inertial();
+        data.scrollEnd.synthetic = event.synthetic();
     } else if (event.type() == EventTypeNames::gesturescrollupdate) {
         type = GestureScrollUpdate;
+        data.scrollUpdate.deltaUnits = toWebGestureScrollUnits(event.deltaUnits());
         data.scrollUpdate.deltaX = event.deltaX();
         data.scrollUpdate.deltaY = event.deltaY();
         data.scrollUpdate.inertial = event.inertial();
diff --git a/third_party/WebKit/Source/web/tests/WebInputEventConversionTest.cpp b/third_party/WebKit/Source/web/tests/WebInputEventConversionTest.cpp
index b852d84..5c38d5b 100644
--- a/third_party/WebKit/Source/web/tests/WebInputEventConversionTest.cpp
+++ b/third_party/WebKit/Source/web/tests/WebInputEventConversionTest.cpp
@@ -993,4 +993,74 @@ TEST(WebInputEventConversionTest, PlatformWheelEventBuilder)
     }
 }
 
+TEST(WebInputEventConversionTest, PlatformGestureEventBuilder)
+{
+    const std::string baseURL("http://www.test8.com/");
+    const std::string fileName("fixed_layout.html");
+
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(baseURL.c_str()), WebString::fromUTF8("fixed_layout.html"));
+    FrameTestHelpers::WebViewHelper webViewHelper;
+    WebViewImpl* webViewImpl = webViewHelper.initializeAndLoad(baseURL + fileName, true);
+    int pageWidth = 640;
+    int pageHeight = 480;
+    webViewImpl->resize(WebSize(pageWidth, pageHeight));
+    webViewImpl->updateAllLifecyclePhases();
+
+    FrameView* view = toLocalFrame(webViewImpl->page()->mainFrame())->view();
+
+    {
+        WebGestureEvent webGestureEvent;
+        webGestureEvent.type = WebInputEvent::GestureScrollBegin;
+        webGestureEvent.x = 0;
+        webGestureEvent.y = 5;
+        webGestureEvent.globalX = 10;
+        webGestureEvent.globalY = 15;
+        webGestureEvent.sourceDevice = WebGestureDeviceTouchpad;
+        webGestureEvent.resendingPluginId = 2;
+        webGestureEvent.data.scrollBegin.inertial = true;
+        webGestureEvent.data.scrollBegin.synthetic = true;
+        webGestureEvent.data.scrollBegin.deltaXHint = 100;
+        webGestureEvent.data.scrollBegin.deltaYHint = 10;
+        webGestureEvent.data.scrollBegin.deltaHintUnits = WebGestureEvent::Pixels;
+
+        PlatformGestureEventBuilder platformGestureBuilder(view, webGestureEvent);
+        EXPECT_EQ(PlatformGestureSourceTouchpad, platformGestureBuilder.source());
+        EXPECT_EQ(2, platformGestureBuilder.resendingPluginId());
+        EXPECT_EQ(0, platformGestureBuilder.position().x());
+        EXPECT_EQ(5, platformGestureBuilder.position().y());
+        EXPECT_EQ(10, platformGestureBuilder.globalPosition().x());
+        EXPECT_EQ(15, platformGestureBuilder.globalPosition().y());
+        EXPECT_TRUE(platformGestureBuilder.inertial());
+        EXPECT_TRUE(platformGestureBuilder.synthetic());
+        EXPECT_EQ(100, platformGestureBuilder.deltaX());
+        EXPECT_EQ(10, platformGestureBuilder.deltaY());
+        EXPECT_EQ(ScrollGranularity::ScrollByPixel, platformGestureBuilder.deltaUnits());
+    }
+
+    {
+        WebGestureEvent webGestureEvent;
+        webGestureEvent.type = WebInputEvent::GestureScrollEnd;
+        webGestureEvent.x = 0;
+        webGestureEvent.y = 5;
+        webGestureEvent.globalX = 10;
+        webGestureEvent.globalY = 15;
+        webGestureEvent.sourceDevice = WebGestureDeviceTouchpad;
+        webGestureEvent.resendingPluginId = 2;
+        webGestureEvent.data.scrollEnd.inertial = false;
+        webGestureEvent.data.scrollEnd.synthetic = true;
+        webGestureEvent.data.scrollEnd.deltaUnits = WebGestureEvent::Page;
+
+        PlatformGestureEventBuilder platformGestureBuilder(view, webGestureEvent);
+        EXPECT_EQ(PlatformGestureSourceTouchpad, platformGestureBuilder.source());
+        EXPECT_EQ(2, platformGestureBuilder.resendingPluginId());
+        EXPECT_EQ(0, platformGestureBuilder.position().x());
+        EXPECT_EQ(5, platformGestureBuilder.position().y());
+        EXPECT_EQ(10, platformGestureBuilder.globalPosition().x());
+        EXPECT_EQ(15, platformGestureBuilder.globalPosition().y());
+        EXPECT_FALSE(platformGestureBuilder.inertial());
+        EXPECT_TRUE(platformGestureBuilder.synthetic());
+        EXPECT_EQ(ScrollGranularity::ScrollByPage, platformGestureBuilder.deltaUnits());
+    }
+}
+
 } // namespace blink