Fire attributeChangedCallback on style changes for Custom Elements V1

third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp

Index: third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp
diff --git a/third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp b/third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp
index a2ce75170ba209a48736ae5d9649a8cf49ea315b..8d8dff7df82100494cac119e3f737d513ef0ac1a 100644
--- a/third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp
+++ b/third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp
@@ -34,6 +34,8 @@
 #include "core/dom/MutationRecord.h"
 #include "core/dom/StyleChangeReason.h"
 #include "core/dom/StyleEngine.h"
+#include "core/dom/custom/CustomElement.h"
+#include "core/dom/custom/CustomElementDefinition.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
@@ -41,6 +43,15 @@ namespace blink {
 
 namespace {
 
+static CustomElementDefinition* definitionIfStyleChangedCallback(Element* element)
+{
+    if (!element || element->getCustomElementState() != CustomElementState::Custom)

[dominicc (has gone to gerrit), 2016/07/22 01:14:01]

I'm guessing if it is worth doing here, it is worth doing everywhere. Why not
make definitionForElement have an inlineable wrapper which checks
CustomElementState and does the early return.

+        return nullptr;
+    CustomElementDefinition* definition = CustomElement::definitionForElement(*element);
+    DCHECK(definition);
+    return definition->hasStyleAttributeChangedCallback() ? definition : nullptr;
+}
+
 class StyleAttributeMutationScope {
     WTF_MAKE_NONCOPYABLE(StyleAttributeMutationScope);
     STACK_ALLOCATED();
@@ -65,13 +76,14 @@ public:
         m_mutationRecipients = MutationObserverInterestGroup::createForAttributesMutation(*s_currentDecl->parentElement(), HTMLNames::styleAttr);
         if (m_mutationRecipients && m_mutationRecipients->isOldValueRequested())

[dominicc (has gone to gerrit), 2016/07/22 01:14:01]

I wonder if this is clearer by simply declaring

bool shouldReadOldValue = ...mutation observer part... || ...custom element
part...;

             shouldReadOldValue = true;
+        else if (definitionIfStyleChangedCallback(s_currentDecl->parentElement()))
+            shouldReadOldValue = true;
 
-        AtomicString oldValue;
         if (shouldReadOldValue)
-            oldValue = s_currentDecl->parentElement()->getAttribute(HTMLNames::styleAttr);
+            m_oldValue = s_currentDecl->parentElement()->getAttribute(HTMLNames::styleAttr);
 
         if (m_mutationRecipients) {
-            AtomicString requestedOldValue = m_mutationRecipients->isOldValueRequested() ? oldValue : nullAtom;
+            AtomicString requestedOldValue = m_mutationRecipients->isOldValueRequested() ? m_oldValue : nullAtom;
             m_mutation = MutationRecord::createAttributes(s_currentDecl->parentElement(), HTMLNames::styleAttr, requestedOldValue);
         }
     }
@@ -82,10 +94,19 @@ public:
         if (s_scopeCount)
             return;
 
-        if (m_mutation && s_shouldDeliver)
-            m_mutationRecipients->enqueueMutationRecord(m_mutation);
+        if (s_shouldDeliver) {
+            if (m_mutation)
+                m_mutationRecipients->enqueueMutationRecord(m_mutation);
+
+            Element* element = s_currentDecl->parentElement();
+            if (CustomElementDefinition* definition = definitionIfStyleChangedCallback(element)) {
+                definition->enqueueAttributeChangedCallback(element,
+                    HTMLNames::styleAttr, m_oldValue,
+                    element->getAttribute(HTMLNames::styleAttr));
+            }
 
-        s_shouldDeliver = false;
+            s_shouldDeliver = false;
+        }
 
         // We have to clear internal state before calling Inspector's code.
         AbstractPropertySetCSSStyleDeclaration* localCopyStyleDecl = s_currentDecl;
@@ -117,6 +138,7 @@ private:
 
     Member<MutationObserverInterestGroup> m_mutationRecipients;
     Member<MutationRecord> m_mutation;
+    AtomicString m_oldValue;
 };
 
 unsigned StyleAttributeMutationScope::s_scopeCount = 0;