QPropertyBindingPrivate: de-inline functions that modify heapObservers

Manipulating owning containers is costly at runtime, but also at
compile-time, so don't do it in inline functions, do it
out-of-line.

Removes the top-2 entries[1] in a Clang -ftime-trace QtWidget build.

[1] at the time of writing of this patch

Change-Id: I5da5030788b0d976a0ab7875f87ba3b51dbb1231
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/corelib/kernel/qproperty.cpp

@@ -245,6 +245,24 @@ QPropertyBindingPrivate::~QPropertyBindingPrivate()
                         + QPropertyBindingPrivate::getSizeEnsuringAlignment());
 }
 
+void QPropertyBindingPrivate::clearDependencyObservers() {
+    for (size_t i = 0; i < qMin(dependencyObserverCount, inlineDependencyObservers.size()); ++i) {
+        QPropertyObserverPointer p{&inlineDependencyObservers[i]};
+        p.unlink_fast();
+    }
+    if (heapObservers)
+        heapObservers->clear();
+    dependencyObserverCount = 0;
+}
+
+QPropertyObserverPointer QPropertyBindingPrivate::allocateDependencyObserver_slow()
+{
+    ++dependencyObserverCount;
+    if (!heapObservers)
+        heapObservers.reset(new std::vector<QPropertyObserver>());
+    return {&heapObservers->emplace_back()};
+}
+
 void QPropertyBindingPrivate::unlinkAndDeref()
 {
     clearDependencyObservers();

src/corelib/kernel/qproperty_p.h

@@ -295,15 +295,7 @@ public:
         return observers;
     }
 
-    void clearDependencyObservers() {
-        for (size_t i = 0; i < qMin(dependencyObserverCount, inlineDependencyObservers.size()); ++i) {
-            QPropertyObserverPointer p{&inlineDependencyObservers[i]};
-            p.unlink_fast();
-        }
-        if (heapObservers)
-            heapObservers->clear();
-        dependencyObserverCount = 0;
-    }
+    void clearDependencyObservers();
 
     Q_ALWAYS_INLINE QPropertyObserverPointer allocateDependencyObserver() {
         if (dependencyObserverCount < inlineDependencyObservers.size()) {
@@ -313,13 +305,7 @@ public:
         return allocateDependencyObserver_slow();
     }
 
-    Q_NEVER_INLINE QPropertyObserverPointer allocateDependencyObserver_slow()
-    {
-        ++dependencyObserverCount;
-        if (!heapObservers)
-            heapObservers.reset(new std::vector<QPropertyObserver>());
-        return {&heapObservers->emplace_back()};
-    }
+    QPropertyObserverPointer allocateDependencyObserver_slow();
 
     QPropertyBindingSourceLocation sourceLocation() const
     {