[DevTools] Handle iframes when forcing contexts on runtime.enable.

third_party/WebKit/Source/core/inspector/PageRuntimeAgent.cpp

Index: third_party/WebKit/Source/core/inspector/PageRuntimeAgent.cpp
diff --git a/third_party/WebKit/Source/core/inspector/PageRuntimeAgent.cpp b/third_party/WebKit/Source/core/inspector/PageRuntimeAgent.cpp
index ca54c5c391c9a474c4a52e0dc339f1898a2d63dc..0221280acbc34cb4f0814f0a520b363bf72d82e0 100644
--- a/third_party/WebKit/Source/core/inspector/PageRuntimeAgent.cpp
+++ b/third_party/WebKit/Source/core/inspector/PageRuntimeAgent.cpp
@@ -66,8 +66,10 @@ void PageRuntimeAgent::enable(ErrorString* errorString)
         return;
 
     m_instrumentingAgents->setPageRuntimeAgent(this);
-    if (m_inspectedFrames->root()->loader().stateMachine()->committedFirstRealDocumentLoad())
-        m_inspectedFrames->root()->script().initializeMainWorld();
+    if (m_inspectedFrames->root()->loader().stateMachine()->committedFirstRealDocumentLoad()) {
+        for (const LocalFrame* frame : *m_inspectedFrames)
+            frame->script().initializeMainWorld();
+    }
     InspectorRuntimeAgent::enable(errorString);
 }