Add a deprecation warning for notifications on insecure contexts.

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

Index: third_party/WebKit/Source/core/frame/Deprecation.cpp
diff --git a/third_party/WebKit/Source/core/frame/Deprecation.cpp b/third_party/WebKit/Source/core/frame/Deprecation.cpp
index 81f66ffe13713b57cee662ae4f766601703474de..cd5cf67b26823934f40ae231ccd26a6dd7555806 100644
--- a/third_party/WebKit/Source/core/frame/Deprecation.cpp
+++ b/third_party/WebKit/Source/core/frame/Deprecation.cpp
@@ -19,6 +19,7 @@ enum Milestone {
   M57,
   M58,
   M59,
+  M60,
 };
 
 const char* milestoneString(Milestone milestone) {
@@ -34,6 +35,8 @@ const char* milestoneString(Milestone milestone) {
       return "M58, around April 2017";
     case M59:
       return "M59, around June 2017";
+    case M60:
+      return "M60, around August 2017";
   }
 
   ASSERT_NOT_REACHED();
@@ -354,6 +357,16 @@ String Deprecation::deprecationMessage(UseCounter::Feature feature) {
              "switching your application to a secure origin, such as HTTPS. "
              "See https://goo.gl/rStTGz for more details.";
 
+    case UseCounter::NotificationInsecureOrigin:
+    case UseCounter::NotificationAPIInsecureOriginIframe:
+    case UseCounter::NotificationPermissionRequestedInsecureOrigin:
+      return String::format(
+          "Using the Notification API on insecure origins is "
+          "deprecated and will be removed in %s. You should consider "
+          "switching your application to a secure origin, such as HTTPS. See "
+          "https://goo.gl/rStTGz for more details.",
+          milestoneString(M60));
+
     case UseCounter::ElementCreateShadowRootMultiple:
       return "Calling Element.createShadowRoot() for an element which already "
              "hosts a shadow root is deprecated. See "