Add a WebDocument::watchCssSelectors(selectors)

Source/core/rendering/style/StyleRareNonInheritedData.cpp

Index: Source/core/rendering/style/StyleRareNonInheritedData.cpp
diff --git a/Source/core/rendering/style/StyleRareNonInheritedData.cpp b/Source/core/rendering/style/StyleRareNonInheritedData.cpp
index e4d640ab9c00c38bc0e79353794b367adcc39b72..19939afd7e824dc388c5d04d3db7a67c27507d47 100644
--- a/Source/core/rendering/style/StyleRareNonInheritedData.cpp
+++ b/Source/core/rendering/style/StyleRareNonInheritedData.cpp
@@ -22,6 +22,7 @@
 #include "config.h"
 #include "core/rendering/style/StyleRareNonInheritedData.h"
 
+#include "core/dom/Document.h"
 #include "core/dom/WebCoreMemoryInstrumentation.h"
 #include "core/rendering/style/ContentData.h"
 #include "core/rendering/style/RenderStyle.h"
@@ -52,6 +53,9 @@ StyleRareNonInheritedData::StyleRareNonInheritedData()
     , m_clipPath(RenderStyle::initialClipPath())
     , m_visitedLinkBackgroundColor(RenderStyle::initialBackgroundColor())
     , m_order(RenderStyle::initialOrder())
+#if ENABLE(CSS_CALLBACKS)
+    , m_document()

[abarth-chromium, 2013/07/12 23:44:11]

Why do you need this explicit call to the constructor?  I'd think the implicit
call would be sufficient.

[Jeffrey Yasskin, 2013/07/16 00:38:51]

I don't. That's a remnant from an earlier version of the patch. Removed.

+#endif
     , m_flowThread(RenderStyle::initialFlowThread())
     , m_regionThread(RenderStyle::initialRegionThread())
     , m_regionFragment(RenderStyle::initialRegionFragment())
@@ -124,6 +128,9 @@ StyleRareNonInheritedData::StyleRareNonInheritedData(const StyleRareNonInherited
     , m_visitedLinkBorderTopColor(o.m_visitedLinkBorderTopColor)
     , m_visitedLinkBorderBottomColor(o.m_visitedLinkBorderBottomColor)
     , m_order(o.m_order)
+#if ENABLE(CSS_CALLBACKS)
+    , m_document()
+#endif
     , m_flowThread(o.m_flowThread)
     , m_regionThread(o.m_regionThread)
     , m_regionFragment(o.m_regionFragment)
@@ -156,6 +163,14 @@ StyleRareNonInheritedData::StyleRareNonInheritedData(const StyleRareNonInherited
 
 StyleRareNonInheritedData::~StyleRareNonInheritedData()
 {
+#if ENABLE(CSS_CALLBACKS)
+    if (!m_callbackSelectors.isEmpty() && m_document.get()) {
+        Document* document = m_document.get();
+        for (Vector<String>::const_iterator it = m_callbackSelectors.begin(), end = m_callbackSelectors.end();
+            it != end; ++it)
+            document->removeSelectorMatch(*it);

[esprehn, 2013/07/13 01:43:01]

No need to cache the ptr, m_document->...() is fine. This also looks suspicous,
I think you want to hook Element::recalcStyle and look at the RenderStyle to see
if it has your magic property and bump the counter up and down.

[Jeffrey Yasskin, 2013/07/16 00:38:51]

WTF's WeakPtr doesn't actually have an operator->, but I can switch to
m_document.get()->...()
I was trying to avoid adding any code to the non-rare path, but I can definitely
switch to 'if's in recalcStyle and probably ~Element. I'll do that after writing
some benchmarks to see if it has any effect on performance.

+    }
+#endif
 }
 
 bool StyleRareNonInheritedData::operator==(const StyleRareNonInheritedData& o) const
@@ -199,6 +214,10 @@ bool StyleRareNonInheritedData::operator==(const StyleRareNonInheritedData& o) c
         && m_visitedLinkBorderTopColor == o.m_visitedLinkBorderTopColor
         && m_visitedLinkBorderBottomColor == o.m_visitedLinkBorderBottomColor
         && m_order == o.m_order
+#if ENABLE(CSS_CALLBACKS)
+        && m_callbackSelectors == o.m_callbackSelectors
+        && m_document.get() == o.m_document.get()
+#endif
         && m_flowThread == o.m_flowThread
         && m_regionThread == o.m_regionThread
         && m_regionFragment == o.m_regionFragment