Expand tap highlight to allow multiple highlights for touch disambiguation.

Source/core/platform/graphics/GraphicsLayer.cpp

 /*
  * Copyright (C) 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 85 matching lines @@
     , m_contentsVisible(true)
     , m_paintingPhase(GraphicsLayerPaintAllWithOverflowClip)
     , m_contentsOrientation(CompositingCoordinatesTopDown)
     , m_parent(0)
     , m_maskLayer(0)
     , m_replicaLayer(0)
     , m_replicatedLayer(0)
     , m_paintCount(0)
     , m_contentsLayer(0)
     , m_contentsLayerId(0)
-    , m_linkHighlight(0)
     , m_contentsLayerPurpose(NoContentsLayer)
     , m_scrollableArea(0)
     , m_compositingReasons(WebKit::CompositingReasonUnknown)
 {
 #ifndef NDEBUG
     if (m_client)
         m_client->verifyNotPainting();
 #endif
 
     m_opaqueRectTrackingContentLayerDelegate = adoptPtr(new OpaqueRectTrackingContentLayerDelegate(this));
     m_layer = adoptPtr(Platform::current()->compositorSupport()->createContentLayer(m_opaqueRectTrackingContentLayerDelegate.get()));
     m_layer->layer()->setDrawsContent(m_drawsContent && m_contentsVisible);
     m_layer->layer()->setWebLayerClient(this);
     m_layer->setAutomaticallyComputeRasterScale(true);
 }
 
 GraphicsLayer::~GraphicsLayer()
 {
-    if (m_linkHighlight) {
-        m_linkHighlight->clearCurrentGraphicsLayer();
-        m_linkHighlight = 0;
-    }
+    for (size_t i = 0; i < m_linkHighlights.size(); i++)

[jochen (gone - plz use gerrit), 2013/09/16 14:13:05]

nit: ++i (and everywhere else)

+        m_linkHighlights[i]->clearCurrentGraphicsLayer();
+    m_linkHighlights.clear();
 
 #ifndef NDEBUG
     if (m_client)
         m_client->verifyNotPainting();
 #endif
 
     if (m_replicaLayer)
         m_replicaLayer->setReplicatedLayer(0);
 
     if (m_replicatedLayer)
@@ skipping 257 matching lines @@
     }
 
     const Vector<GraphicsLayer*>& childLayers = children();
     size_t numChildren = childLayers.size();
     for (size_t i = 0; i < numChildren; ++i) {
         GraphicsLayer* curChild = childLayers[i];
 
         childHost->addChild(curChild->platformLayer());
     }
 
-    if (m_linkHighlight)
-        childHost->addChild(m_linkHighlight->layer());
+    for (size_t i = 0; i < m_linkHighlights.size(); i++)
+        childHost->addChild(m_linkHighlights[i]->layer());
 }
 
 void GraphicsLayer::updateLayerIsDrawable()
 {
     // For the rest of the accelerated compositor code, there is no reason to make a
     // distinction between drawsContent and contentsVisible. So, for m_layer->layer(), these two
     // flags are combined here. m_contentsLayer shouldn't receive the drawsContent flag
     // so it is only given contentsVisible.
 
     m_layer->layer()->setDrawsContent(m_drawsContent && m_contentsVisible);
     if (WebLayer* contentsLayer = contentsLayerIfRegistered())
         contentsLayer->setDrawsContent(m_contentsVisible);
 
     if (m_drawsContent) {
         m_layer->layer()->invalidate();
-        if (m_linkHighlight)
-            m_linkHighlight->invalidate();
+        for (size_t i = 0; i < m_linkHighlights.size(); i++)
+            m_linkHighlights[i]->invalidate();
     }
 }
 
 void GraphicsLayer::updateContentsRect()
 {
     WebLayer* contentsLayer = contentsLayerIfRegistered();
     if (!contentsLayer)
         return;
 
     contentsLayer->setPosition(FloatPoint(m_contentsRect.x(), m_contentsRect.y()));
@@ skipping 304 matching lines @@
     dumpLayer(ts, 0, flags);
     return ts.release();
 }
 
 WebKit::WebString GraphicsLayer::debugName(WebKit::WebLayer* webLayer)
 {
     String name;
     if (!m_client)
         return name;
 
+    String highlightDebugName;
+    for (size_t i = 0; i < m_linkHighlights.size(); i++) {
+        if (webLayer == m_linkHighlights[i]->layer()) {
+            highlightDebugName = "LinkHighlight[" + String::number(i) + "] for " + m_client->debugName(this);
+            break;
+        }
+    }
+
     if (webLayer == m_contentsLayer) {
         name = "ContentsLayer for " + m_client->debugName(this);
-    } else if (m_linkHighlight && webLayer == m_linkHighlight->layer()) {
-        name = "LinkHighlight for " + m_client->debugName(this);
+    } else if (!highlightDebugName.isEmpty()) {
+        name = highlightDebugName;
     } else if (webLayer == m_layer->layer()) {
         name = m_client->debugName(this);
     } else {
         ASSERT_NOT_REACHED();
     }
     return name;
 }
 
 void GraphicsLayer::setCompositingReasons(WebKit::WebCompositingReasons reasons)
 {
@@ skipping 126 matching lines @@
         contentsLayer->invalidate();
         addRepaintRect(contentsRect());
     }
 }
 
 void GraphicsLayer::setNeedsDisplay()
 {
     if (drawsContent()) {
         m_layer->layer()->invalidate();
         addRepaintRect(FloatRect(FloatPoint(), m_size));
-        if (m_linkHighlight)
-            m_linkHighlight->invalidate();
+        for (size_t i = 0; i < m_linkHighlights.size(); i++)
+            m_linkHighlights[i]->invalidate();
     }
 }
 
 void GraphicsLayer::setNeedsDisplayInRect(const FloatRect& rect)
 {
     if (drawsContent()) {
         m_layer->layer()->invalidateRect(rect);
         addRepaintRect(rect);
-        if (m_linkHighlight)
-            m_linkHighlight->invalidate();
+        for (size_t i = 0; i < m_linkHighlights.size(); i++)
+            m_linkHighlights[i]->invalidate();
     }
 }
 
 void GraphicsLayer::setContentsRect(const IntRect& rect)
 {
     if (rect == m_contentsRect)
         return;
 
     m_contentsRect = rect;
     updateContentsRect();
@@ skipping 220 matching lines @@
 }
 
 void GraphicsLayer::setBackgroundFilters(const FilterOperations& filters)
 {
     OwnPtr<WebFilterOperations> webFilters = adoptPtr(Platform::current()->compositorSupport()->createFilterOperations());
     if (!copyWebCoreFilterOperationsToWebFilterOperations(filters, *webFilters))
         return;
     m_layer->layer()->setBackgroundFilters(*webFilters);
 }
 
-void GraphicsLayer::setLinkHighlight(LinkHighlightClient* linkHighlight)
+void GraphicsLayer::addLinkHighlight(LinkHighlightClient* linkHighlight)
 {
-    m_linkHighlight = linkHighlight;
-    if (m_linkHighlight)
-        m_linkHighlight->layer()->setWebLayerClient(this);
+    ASSERT(linkHighlight);
+    m_linkHighlights.append(linkHighlight);
+    linkHighlight->layer()->setWebLayerClient(this);
     updateChildList();
 }
 
+void GraphicsLayer::removeLinkHighlight(LinkHighlightClient* linkHighlight)
+{
+    m_linkHighlights.remove(m_linkHighlights.find(linkHighlight));
+    ASSERT(!m_linkHighlights.contains(linkHighlight));

[jochen (gone - plz use gerrit), 2013/09/16 14:13:05]

why not assert that you don't add the same client twice instead of here when
removing clients?

I would expect that the stack trace when addnig the client twice is (slightly)
more interesting

+    updateChildList();
+}
+
 void GraphicsLayer::setScrollableArea(ScrollableArea* scrollableArea, bool isMainFrame)
 {
     if (m_scrollableArea == scrollableArea)
         return;
 
     m_scrollableArea = scrollableArea;
 
     // Main frame scrolling may involve pinch zoom and gets routed through
     // WebViewImpl explicitly rather than via GraphicsLayer::didScroll.
     if (isMainFrame)
@@ skipping 30 matching lines @@
 #ifndef NDEBUG
 void showGraphicsLayerTree(const WebCore::GraphicsLayer* layer)
 {
     if (!layer)
         return;
 
     String output = layer->layerTreeAsText(WebCore::LayerTreeIncludesDebugInfo);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif