Reduce hit test on ShowPress by moving event targeting to WebViewImpl

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 7f6775e22c3486d7aa8d72b3b8f70bf9e34103d0..ea59192fa1cc827a913b410c755b6191eea694e0 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -71,7 +71,6 @@
 #include "core/page/DragData.h"
 #include "core/page/DragSession.h"
 #include "core/page/EventHandler.h"
-#include "core/page/EventWithHitTestResults.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/InjectedStyleSheets.h"
@@ -658,15 +657,18 @@ bool WebViewImpl::handleGestureEvent(const WebGestureEvent& event)
 
     PlatformGestureEventBuilder platformEvent(mainFrameImpl()->frameView(), event);
 
-    // FIXME: Remove redundant hit tests by pushing the call to EventHandler::targetGestureEvent
-    // up to this point and pass GestureEventWithHitTestResults around.
+    HitTestResult emptyResult;

[Rick Byers, 2014/08/20 23:59:33]

As discussed, having this "sometimes targetted but sometimes not" event is
error-prone.  You can split the code paths up further into methods that take a
fully targetted event and those that don't.

[Zeeshan Qureshi, 2014/08/21 04:59:25]

Done.

+    GestureEventWithHitTestResults targetedEvent(platformEvent, emptyResult);
+    // Hit test across all frames and do touch adjustment as necessary for the event type.
+    if (!platformEvent.isScrollEvent())
+        targetedEvent = m_page->deprecatedLocalMainFrame()->eventHandler().targetGestureEvent(platformEvent);
 
     // Handle link highlighting outside the main switch to avoid getting lost in the
     // complicated set of cases handled below.
     switch (event.type) {
     case WebInputEvent::GestureShowPress:
         // Queue a highlight animation, then hand off to regular handler.
-        enableTapHighlightAtPoint(platformEvent);
+        enableTapHighlightAtPoint(targetedEvent);
         break;
     case WebInputEvent::GestureTapCancel:
     case WebInputEvent::GestureTap:
@@ -681,7 +683,7 @@ bool WebViewImpl::handleGestureEvent(const WebGestureEvent& event)
     switch (event.type) {
     case WebInputEvent::GestureTap: {
         m_client->cancelScheduledContentIntents();
-        if (detectContentOnTouch(platformEvent.position())) {
+        if (detectContentOnTouch(targetedEvent.event().position())) {

[Rick Byers, 2014/08/20 23:59:32]

Add FIXME to use the targeted event here.

[Zeeshan Qureshi, 2014/08/21 04:59:25]

Done.

             eventSwallowed = true;
             break;
         }
@@ -717,7 +719,7 @@ bool WebViewImpl::handleGestureEvent(const WebGestureEvent& event)
             }
         }
 
-        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(platformEvent);
+        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(targetedEvent);
 
         if (m_selectPopup && m_selectPopup == selectPopup) {
             // That tap triggered a select popup which is the same as the one that
@@ -738,20 +740,20 @@ bool WebViewImpl::handleGestureEvent(const WebGestureEvent& event)
         m_client->cancelScheduledContentIntents();
         m_page->contextMenuController().clearContextMenu();
         m_contextMenuAllowed = true;
-        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(platformEvent);
+        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(targetedEvent);
         m_contextMenuAllowed = false;
 
         break;
     }
     case WebInputEvent::GestureShowPress: {
         m_client->cancelScheduledContentIntents();
-        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(platformEvent);
+        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(targetedEvent);
         break;
     }
     case WebInputEvent::GestureDoubleTap:
         if (m_webSettings->doubleTapToZoomEnabled() && minimumPageScaleFactor() != maximumPageScaleFactor()) {
             m_client->cancelScheduledContentIntents();
-            animateDoubleTapZoom(platformEvent.position());
+            animateDoubleTapZoom(targetedEvent.event().position());
         }
         // GestureDoubleTap is currently only used by Android for zooming. For WebCore,
         // GestureTap with tap count = 2 is used instead. So we drop GestureDoubleTap here.
@@ -769,7 +771,7 @@ bool WebViewImpl::handleGestureEvent(const WebGestureEvent& event)
     case WebInputEvent::GesturePinchEnd:
     case WebInputEvent::GesturePinchUpdate:
     case WebInputEvent::GestureFlingStart: {
-        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(platformEvent);
+        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(targetedEvent);
         break;
     }
     default:
@@ -1189,17 +1191,14 @@ static bool showsHandCursor(Node* node, LocalFrame* frame)
         || (cursor == CURSOR_AUTO && frame->eventHandler().useHandCursor(node, node->isLink()));
 }
 
-Node* WebViewImpl::bestTapNode(const PlatformGestureEvent& tapEvent)
+Node* WebViewImpl::bestTapNode(const GestureEventWithHitTestResults& targetedTapEvent)
 {
     TRACE_EVENT0("input", "WebViewImpl::bestTapNode");
 
     if (!m_page || !m_page->mainFrame())
         return 0;
 
-    // FIXME: Rely on earlier hit test instead of hit testing again.
-    GestureEventWithHitTestResults targetedEvent =
-        m_page->deprecatedLocalMainFrame()->eventHandler().targetGestureEvent(tapEvent, true);
-    Node* bestTouchNode = targetedEvent.hitTestResult().targetNode();
+    Node* bestTouchNode = targetedTapEvent.hitTestResult().targetNode();
 
     // We might hit something like an image map that has no renderer on it
     // Walk up the tree until we have a node with an attached renderer
@@ -1225,9 +1224,9 @@ Node* WebViewImpl::bestTapNode(const PlatformGestureEvent& tapEvent)
     return bestTouchNode;
 }
 
-void WebViewImpl::enableTapHighlightAtPoint(const PlatformGestureEvent& tapEvent)
+void WebViewImpl::enableTapHighlightAtPoint(const GestureEventWithHitTestResults& targetedTapEvent)
 {
-    Node* touchNode = bestTapNode(tapEvent);
+    Node* touchNode = bestTapNode(targetedTapEvent);
 
     WillBeHeapVector<RawPtrWillBeMember<Node> > highlightNodes;
     highlightNodes.append(touchNode);