Add deprecation message for -webkit-background-composite

third_party/WebKit/Source/core/frame/UseCounter.cpp

Index: third_party/WebKit/Source/core/frame/UseCounter.cpp
diff --git a/third_party/WebKit/Source/core/frame/UseCounter.cpp b/third_party/WebKit/Source/core/frame/UseCounter.cpp
index 8e65609f65e41de83e72a10607d5b498947a6ca7..bdcbbb28d6134a13388854ed2e2c51340be60691 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.cpp
+++ b/third_party/WebKit/Source/core/frame/UseCounter.cpp
@@ -706,6 +706,16 @@ void UseCounter::countDeprecation(const LocalFrame* frame, Feature feature)
     }
 }
 
+void UseCounter::showDeprecationWarning(const LocalFrame* frame, CSSPropertyID cssPropertyID)
+{
+    if (!frame || !frame->host())
+        return;
+
+    String message = deprecationMessage(cssPropertyID);
+    if (!message.isEmpty())
+        frame->console().addMessage(ConsoleMessage::create(DeprecationMessageSource, WarningMessageLevel, message));
+}
+
 void UseCounter::countDeprecation(ExecutionContext* context, Feature feature)
 {
     if (!context)
@@ -735,6 +745,8 @@ static const char* milestoneString(int milestone)
     switch (milestone) {
     case 50:
         return "M50, around April 2016";
+    case 51:
+        return "M51, around June 2016";
     case 53:
         return "M53, around September 2016";
     }
@@ -758,6 +770,16 @@ static String replacedWillBeRemoved(const char* feature, const char* replacement
     return String::format("%s is deprecated and will be removed in %s. Please use %s instead. See https://www.chromestatus.com/features/%s for more details.", feature, milestoneString(milestone), replacement, details);
 }
 
+String UseCounter::deprecationMessage(CSSPropertyID cssPropertyID)
+{
+    switch (cssPropertyID) {
+    case CSSPropertyWebkitBackgroundComposite:
+        return willBeRemoved("'-webkit-background-composite'", 51, "6607299456008192");
+    default:
+        return emptyString();
+    }
+}
+
 String UseCounter::deprecationMessage(Feature feature)
 {
     switch (feature) {