Measure the usage of cross-origin modal dialogs.

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

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index 20a01b9f6b24d98edfe157a16ae76c19f7f7615c..e8858af8d9a127c8f92a273aca8651cefadeb058 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -764,6 +764,10 @@ void LocalDOMWindow::print(ScriptState* scriptState)
         m_shouldPrintWhenFinishedLoading = true;
         return;
     }
+
+    if (frame()->isCrossOrigin())
+        UseCounter::count(frame()->document(), UseCounter::CrossOriginWindowPrint);
+
     m_shouldPrintWhenFinishedLoading = false;
     host->chromeClient().print(frame());
 }
@@ -802,6 +806,9 @@ void LocalDOMWindow::alert(ScriptState* scriptState, const String& message)
     if (!host)
         return;
 
+    if (frame()->isCrossOrigin())
+        UseCounter::count(frame()->document(), UseCounter::CrossOriginWindowAlert);
+
     host->chromeClient().openJavaScriptAlert(frame(), message);
 }
 
@@ -832,6 +839,9 @@ bool LocalDOMWindow::confirm(ScriptState* scriptState, const String& message)
     if (!host)
         return false;
 
+    if (frame()->isCrossOrigin())
+        UseCounter::count(frame()->document(), UseCounter::CrossOriginWindowConfirm);
+
     return host->chromeClient().openJavaScriptConfirm(frame(), message);
 }
 
@@ -866,6 +876,9 @@ String LocalDOMWindow::prompt(ScriptState* scriptState, const String& message, c
     if (host->chromeClient().openJavaScriptPrompt(frame(), message, defaultValue, returnValue))
         return returnValue;
 
+    if (frame()->isCrossOrigin())
+        UseCounter::count(frame()->document(), UseCounter::CrossOriginWindowPrompt);
+
     return String();
 }