Add deprecation message for -webkit-background-composite

third_party/WebKit/Source/core/frame/FrameHost.h

Index: third_party/WebKit/Source/core/frame/FrameHost.h
diff --git a/third_party/WebKit/Source/core/frame/FrameHost.h b/third_party/WebKit/Source/core/frame/FrameHost.h
index 5931a4781c8d1616a9839d03d59ffd17f502c531..1780acdb8974d4ad363274adfe51264ebfabdb6c 100644
--- a/third_party/WebKit/Source/core/frame/FrameHost.h
+++ b/third_party/WebKit/Source/core/frame/FrameHost.h
@@ -45,6 +45,7 @@ namespace blink {
 
 class ChromeClient;
 class ConsoleMessageStorage;
+class Deprecation;
 class EventHandlerRegistry;
 class Page;
 class PageScaleConstraintsSet;
@@ -72,6 +73,7 @@ public:
     Settings& settings() const;
     ChromeClient& chromeClient() const;
     UseCounter& useCounter() const;
+    Deprecation& deprecation() const;
 
     // Corresponds to pixel density of the device where this Page is
     // being displayed. In multi-monitor setups this can vary between pages.