Reduce hit test on ShowPress by moving event targeting to WebViewImpl

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 54 matching lines @@
 #include "core/loader/DocumentLoader.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/UniqueIdentifier.h"
 #include "core/page/Chrome.h"
 #include "core/page/ContextMenuController.h"
 #include "core/page/ContextMenuProvider.h"
 #include "core/page/DragController.h"
 #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"
 #include "core/page/Page.h"
 #include "core/page/PagePopupClient.h"
 #include "core/page/PointerLockController.h"
 #include "core/page/ScopedPageLoadDeferrer.h"
 #include "core/page/TouchDisambiguation.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/RenderWidget.h"
@@ skipping 584 matching lines @@
             eventSwallowed = true;
 
         m_client->didHandleGestureEvent(event, eventCancelled);
         return eventSwallowed;
     default:
         break;
     }
 
     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.
+    // Special handling for double tap and scroll events as we don't want to
+    // hit test for them.
+    switch (event.type) {
+    case WebInputEvent::GestureDoubleTap:
+        if (m_webSettings->doubleTapToZoomEnabled() && minimumPageScaleFactor() != maximumPageScaleFactor()) {
+            m_client->cancelScheduledContentIntents();
+            animateDoubleTapZoom(platformEvent.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.
+        eventSwallowed = true;
+        m_client->didHandleGestureEvent(event, eventCancelled);
+        return eventSwallowed;
+    case WebInputEvent::GestureScrollBegin:
+    case WebInputEvent::GesturePinchBegin:
+        m_client->cancelScheduledContentIntents();
+    case WebInputEvent::GestureScrollEnd:
+    case WebInputEvent::GestureScrollUpdate:
+    case WebInputEvent::GestureScrollUpdateWithoutPropagation:
+    case WebInputEvent::GesturePinchEnd:
+    case WebInputEvent::GesturePinchUpdate:
+    case WebInputEvent::GestureFlingStart:
+        // Scrolling-related gesture events invoke EventHandler recursively for each frame down
+        // the chain, doing a single-frame hit-test per frame. This matches handleWheelEvent.
+        // Perhaps we could simplify things by rewriting scroll handling to work inner frame
+        // out, and then unify with other gesture events.
+        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureScrollEvent(platformEvent);
+        m_client->didHandleGestureEvent(event, eventCancelled);
+        return eventSwallowed;
+    default:
+        break;
+    }
+
+    // Hit test across all frames and do touch adjustment as necessary for the event type.
+    GestureEventWithHitTestResults 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:
     case WebInputEvent::GestureLongPress:
         for (size_t i = 0; i < m_linkHighlights.size(); ++i)
             m_linkHighlights[i]->startHighlightAnimationIfNeeded();
         break;
     default:
         break;
     }
 
     switch (event.type) {
     case WebInputEvent::GestureTap: {
         m_client->cancelScheduledContentIntents();
+        // FIXME: Use targeted event here and save another hit test.
+        // FIXME: Content intent should be generated using same node that was highlighted. crbug.com/416746
         if (detectContentOnTouch(platformEvent.position())) {
             eventSwallowed = true;
             break;
         }
 
         RefPtr<PopupContainer> selectPopup;
         selectPopup = m_selectPopup;
         hideSelectPopup();
         ASSERT(!m_selectPopup);
 
@@ skipping 16 matching lines @@
             if (goodTargets.size() >= 2 && m_client && m_client->didTapMultipleTargets(scaledEvent, goodTargets)) {
                 enableTapHighlights(highlightNodes);
                 for (size_t i = 0; i < m_linkHighlights.size(); ++i)
                     m_linkHighlights[i]->startHighlightAnimationIfNeeded();
                 eventSwallowed = true;
                 eventCancelled = true;
                 break;
             }
         }
 
-        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
             // was showing before the tap. It means the user tapped the select
             // while the popup was showing, and as a result we first closed then
             // immediately reopened the select popup. It needs to be closed.
             hideSelectPopup();
         }
 
         break;
     }
     case WebInputEvent::GestureTwoFingerTap:
     case WebInputEvent::GestureLongPress:
     case WebInputEvent::GestureLongTap: {
         if (!mainFrameImpl() || !mainFrameImpl()->frameView())
             break;
 
         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);
-        break;
-    }
-    case WebInputEvent::GestureDoubleTap:
-        if (m_webSettings->doubleTapToZoomEnabled() && minimumPageScaleFactor() != maximumPageScaleFactor()) {
-            m_client->cancelScheduledContentIntents();
-            animateDoubleTapZoom(platformEvent.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.
-        eventSwallowed = true;
-        break;
-    case WebInputEvent::GestureScrollBegin:
-    case WebInputEvent::GesturePinchBegin:
+    case WebInputEvent::GestureShowPress:
         m_client->cancelScheduledContentIntents();
     case WebInputEvent::GestureTapDown:
-    case WebInputEvent::GestureScrollEnd:
-    case WebInputEvent::GestureScrollUpdate:
-    case WebInputEvent::GestureScrollUpdateWithoutPropagation:
     case WebInputEvent::GestureTapCancel:
-    case WebInputEvent::GestureTapUnconfirmed:
-    case WebInputEvent::GesturePinchEnd:
-    case WebInputEvent::GesturePinchUpdate:
-    case WebInputEvent::GestureFlingStart: {
-        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(platformEvent);
+    case WebInputEvent::GestureTapUnconfirmed: {
+        eventSwallowed = mainFrameImpl()->frame()->eventHandler().handleGestureEvent(targetedEvent);
         break;
     }
     default:
         ASSERT_NOT_REACHED();
     }
     m_client->didHandleGestureEvent(event, eventCancelled);
     return eventSwallowed;
 }
 
 void WebViewImpl::transferActiveWheelFlingAnimation(const WebActiveWheelFlingParameters& parameters)
@@ skipping 402 matching lines @@
 static bool showsHandCursor(Node* node, LocalFrame* frame)
 {
     if (!node || !node->renderer())
         return false;
 
     ECursor cursor = node->renderer()->style()->cursor();
     return cursor == CURSOR_POINTER
         || (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().innerNode();
+    Node* bestTouchNode = targetedTapEvent.hitTestResult().innerNode();
 
     // 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
     // FIXME: This wants to walk composed tree with NodeRenderingTraversal::parent().
     while (bestTouchNode && !bestTouchNode->renderer())
         bestTouchNode = NodeRenderingTraversal::parent(bestTouchNode);
 
     Node* cursorDefiningAncestor =
         findCursorDefiningAncestor(bestTouchNode, m_page->deprecatedLocalMainFrame());
     // We show a highlight on tap only when the current node shows a hand cursor
     if (!cursorDefiningAncestor || !showsHandCursor(cursorDefiningAncestor, m_page->deprecatedLocalMainFrame())) {
         return 0;
     }
 
     // We should pick the largest enclosing node with hand cursor set. We do this by first jumping
     // up to cursorDefiningAncestor (which is already known to have hand cursor set). Then we locate
     // the next cursor-defining ancestor up in the the tree and repeat the jumps as long as the node
     // has hand cursor set.
     do {
         bestTouchNode = cursorDefiningAncestor;
         cursorDefiningAncestor = findCursorDefiningAncestor(NodeRenderingTraversal::parent(bestTouchNode),
             m_page->deprecatedLocalMainFrame());
     } while (cursorDefiningAncestor && showsHandCursor(cursorDefiningAncestor, m_page->deprecatedLocalMainFrame()));
 
     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);
 
     enableTapHighlights(highlightNodes);
 }
 
 void WebViewImpl::enableTapHighlights(WillBeHeapVector<RawPtrWillBeMember<Node> >& highlightNodes)
 {
     if (highlightNodes.isEmpty())
@@ skipping 3108 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink