Change Page::m_mainFrame to be a Frame.

Source/web/InspectorFrontendClientImpl.cpp

Index: Source/web/InspectorFrontendClientImpl.cpp
diff --git a/Source/web/InspectorFrontendClientImpl.cpp b/Source/web/InspectorFrontendClientImpl.cpp
index 6203bb51ef105e9f86a2571ed8ee62537b91c17e..34d0a7d381f2cb2e85b4f1ce6f75ce301417e492 100644
--- a/Source/web/InspectorFrontendClientImpl.cpp
+++ b/Source/web/InspectorFrontendClientImpl.cpp
@@ -63,7 +63,7 @@ void InspectorFrontendClientImpl::windowObjectCleared()
 {
     v8::Isolate* isolate = v8::Isolate::GetCurrent();
     ASSERT(m_frontendPage->mainFrame());
-    ScriptState* scriptState = ScriptState::forMainWorld(m_frontendPage->mainFrame());
+    ScriptState* scriptState = ScriptState::forMainWorld(toLocalFrame(m_frontendPage->mainFrame()));
     ScriptState::Scope scope(scriptState);
 
     if (m_frontendHost)
@@ -73,7 +73,7 @@ void InspectorFrontendClientImpl::windowObjectCleared()
     v8::Handle<v8::Value> frontendHostObj = toV8(m_frontendHost.get(), global, scriptState->isolate());
 
     global->Set(v8::String::NewFromUtf8(isolate, "InspectorFrontendHost"), frontendHostObj);
-    ScriptController* scriptController = m_frontendPage->mainFrame() ? &m_frontendPage->mainFrame()->script() : 0;
+    ScriptController* scriptController = m_frontendPage->mainFrame() ? &toLocalFrame(m_frontendPage->mainFrame())->script() : 0;
     if (scriptController) {
         String installAdditionalAPI =
             "" // Wrap messages that go to embedder.