Require a user gesture to use navigator.share.

third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp

Index: third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp
diff --git a/third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp b/third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp
index 6e4bba14596b7147ffc6f9577a0694a049f2814a..87fa7f0e4d439a2c58a7e702d0a31b8c1103b68c 100644
--- a/third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp
+++ b/third_party/WebKit/Source/modules/webshare/NavigatorShare.cpp
@@ -10,6 +10,7 @@
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Navigator.h"
 #include "modules/webshare/ShareData.h"
+#include "platform/UserGestureIndicator.h"
 #include "platform/mojo/MojoHelper.h"
 #include "public/platform/InterfaceProvider.h"
 #include "public/platform/Platform.h"
@@ -81,6 +82,11 @@ const char* NavigatorShare::supplementName()
 
 ScriptPromise NavigatorShare::share(ScriptState* scriptState, const ShareData& shareData)
 {
+    if (!UserGestureIndicator::utilizeUserGesture()) {
+        DOMException* error = DOMException::create(SecurityError, "Must be handling a user gesture to perform a share request.");
+        return ScriptPromise::rejectWithDOMException(scriptState, error);
+    }
+
     if (!m_service) {
         Document* doc = toDocument(scriptState->getExecutionContext());
         DCHECK(doc);