Disallow certain blocking DOM calls during microtask execution.

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 7ed2ae7975c54c39306c86033b4b31231e0330b5..018ad380a91228ac514394c68c6297dacf0074ee 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -735,7 +735,7 @@ void LocalDOMWindow::blur()
 {
 }
 
-void LocalDOMWindow::print()
+void LocalDOMWindow::print(ScriptState* scriptState)
 {
     if (!frame())
         return;
@@ -752,6 +752,14 @@ void LocalDOMWindow::print()
         }
     }
 
+    if (scriptState && v8::MicrotasksScope::IsRunningMicrotasks(scriptState->isolate())) {
+        Deprecation::countDeprecation(frame()->document(), UseCounter::During_Microtask_Print);
+        if (RuntimeEnabledFeatures::disableBlockingMethodsDuringMicrotasksEnabled()) {
+            frameConsole()->addMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, "Ignored call to 'print()' during microtask execution."));
+            return;
+        }
+    }
+
     if (frame()->isLoading()) {
         m_shouldPrintWhenFinishedLoading = true;
         return;
@@ -767,7 +775,7 @@ void LocalDOMWindow::stop()
     frame()->loader().stopAllLoaders();
 }
 
-void LocalDOMWindow::alert(const String& message)
+void LocalDOMWindow::alert(ScriptState* scriptState, const String& message)
 {
     if (!frame())
         return;
@@ -780,6 +788,14 @@ void LocalDOMWindow::alert(const String& message)
         }
     }
 
+    if (v8::MicrotasksScope::IsRunningMicrotasks(scriptState->isolate())) {
+        Deprecation::countDeprecation(frame()->document(), UseCounter::During_Microtask_Alert);
+        if (RuntimeEnabledFeatures::disableBlockingMethodsDuringMicrotasksEnabled()) {
+            frameConsole()->addMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, "Ignored call to 'alert()' during microtask execution."));
+            return;
+        }
+    }
+
     frame()->document()->updateLayoutTree();
 
     FrameHost* host = frame()->host();
@@ -789,7 +805,7 @@ void LocalDOMWindow::alert(const String& message)
     host->chromeClient().openJavaScriptAlert(frame(), message);
 }
 
-bool LocalDOMWindow::confirm(const String& message)
+bool LocalDOMWindow::confirm(ScriptState* scriptState, const String& message)
 {
     if (!frame())
         return false;
@@ -802,6 +818,14 @@ bool LocalDOMWindow::confirm(const String& message)
         }
     }
 
+    if (v8::MicrotasksScope::IsRunningMicrotasks(scriptState->isolate())) {
+        Deprecation::countDeprecation(frame()->document(), UseCounter::During_Microtask_Confirm);
+        if (RuntimeEnabledFeatures::disableBlockingMethodsDuringMicrotasksEnabled()) {
+            frameConsole()->addMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, "Ignored call to 'confirm()' during microtask execution."));
+            return false;
+        }
+    }
+
     frame()->document()->updateLayoutTree();
 
     FrameHost* host = frame()->host();
@@ -811,7 +835,7 @@ bool LocalDOMWindow::confirm(const String& message)
     return host->chromeClient().openJavaScriptConfirm(frame(), message);
 }
 
-String LocalDOMWindow::prompt(const String& message, const String& defaultValue)
+String LocalDOMWindow::prompt(ScriptState* scriptState, const String& message, const String& defaultValue)
 {
     if (!frame())
         return String();
@@ -824,6 +848,14 @@ String LocalDOMWindow::prompt(const String& message, const String& defaultValue)
         }
     }
 
+    if (v8::MicrotasksScope::IsRunningMicrotasks(scriptState->isolate())) {
+        Deprecation::countDeprecation(frame()->document(), UseCounter::During_Microtask_Prompt);
+        if (RuntimeEnabledFeatures::disableBlockingMethodsDuringMicrotasksEnabled()) {
+            frameConsole()->addMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, "Ignored call to 'prompt()' during microtask execution."));
+            return String();
+        }
+    }
+
     frame()->document()->updateLayoutTree();
 
     FrameHost* host = frame()->host();
@@ -1404,7 +1436,7 @@ void LocalDOMWindow::finishedLoading()
 {
     if (m_shouldPrintWhenFinishedLoading) {
         m_shouldPrintWhenFinishedLoading = false;
-        print();
+        print(nullptr);
     }
 }