Merge r244970 - Null check m_mainFrame in WebPageProxy.cpp

https://bugs.webkit.org/show_bug.cgi?id=197618
<rdar://problem/47463054>

Patch by Alex Christensen <achristensen@webkit.org> on 2019-05-06
Reviewed by Geoffrey Garen.

It's already null checked in some places, and the places where it isn't are causing crashes.
Let's fix all of them.

* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::decidePolicyForNavigationAction):
(WebKit::WebPageProxy::decidePolicyForNewWindowAction):
(WebKit::WebPageProxy::createNewPage):

Source/WebKit/ChangeLog

@@ -1,3 +1,19 @@
+2019-05-06  Alex Christensen  <achristensen@webkit.org>
+
+        Null check m_mainFrame in WebPageProxy.cpp
+        https://bugs.webkit.org/show_bug.cgi?id=197618
+        <rdar://problem/47463054>
+
+        Reviewed by Geoffrey Garen.
+
+        It's already null checked in some places, and the places where it isn't are causing crashes.
+        Let's fix all of them.
+
+        * UIProcess/WebPageProxy.cpp:
+        (WebKit::WebPageProxy::decidePolicyForNavigationAction):
+        (WebKit::WebPageProxy::decidePolicyForNewWindowAction):
+        (WebKit::WebPageProxy::createNewPage):
+
 2019-05-14  Chris Dumez  <cdumez@apple.com>
 
         Crash under WebKit::WebProcessProxy::didBecomeUnresponsive()

Source/WebKit/UIProcess/WebPageProxy.cpp

@@ -4525,7 +4525,10 @@ void WebPageProxy::decidePolicyForNavigationAction(Ref<WebProcessProxy>&& proces
             sourceFrameInfo = API::FrameInfo::create(originatingFrameInfoData, originatingPageID ? process->webPage(originatingPageID) : nullptr);
 
         auto userInitiatedActivity = process->userInitiatedActivity(navigationActionData.userGestureTokenIdentifier);
-        bool shouldOpenAppLinks = !m_shouldSuppressAppLinksInNextNavigationPolicyDecision && destinationFrameInfo->isMainFrame() && !hostsAreEqual(URL({ }, m_mainFrame->url()), request.url()) && navigationActionData.navigationType != WebCore::NavigationType::BackForward;
+        bool shouldOpenAppLinks = !m_shouldSuppressAppLinksInNextNavigationPolicyDecision
+            && destinationFrameInfo->isMainFrame()
+            && (m_mainFrame ? !hostsAreEqual(m_mainFrame->url(), request.url()) : false)
+            && navigationActionData.navigationType != WebCore::NavigationType::BackForward;
 
         auto navigationAction = API::NavigationAction::create(WTFMove(navigationActionData), sourceFrameInfo.get(), destinationFrameInfo.ptr(), WTF::nullopt, WTFMove(request), originalRequest.url(), shouldOpenAppLinks, WTFMove(userInitiatedActivity), mainFrameNavigation);
 
@@ -4642,7 +4645,7 @@ void WebPageProxy::decidePolicyForNewWindowAction(uint64_t frameID, const Securi
             sourceFrameInfo = API::FrameInfo::create(*frame, frameSecurityOrigin.securityOrigin());
 
         auto userInitiatedActivity = m_process->userInitiatedActivity(navigationActionData.userGestureTokenIdentifier);
-        bool shouldOpenAppLinks = !hostsAreEqual(URL({ }, m_mainFrame->url()), request.url());
+        bool shouldOpenAppLinks = m_mainFrame ? !hostsAreEqual(m_mainFrame->url(), request.url()) : false;
         auto navigationAction = API::NavigationAction::create(WTFMove(navigationActionData), sourceFrameInfo.get(), nullptr, frameName, WTFMove(request), URL { }, shouldOpenAppLinks, WTFMove(userInitiatedActivity));
 
         m_navigationClient->decidePolicyForNavigationAction(*this, navigationAction.get(), WTFMove(listener), m_process->transformHandlesToObjects(userData.object()).get());
@@ -4813,7 +4816,7 @@ void WebPageProxy::createNewPage(const FrameInfoData& originatingFrameInfoData,
     MESSAGE_CHECK(m_process, m_process->webFrame(originatingFrameInfoData.frameID));
     auto originatingFrameInfo = API::FrameInfo::create(originatingFrameInfoData, m_process->webPage(originatingPageID));
 
-    auto mainFrameURL = m_mainFrame->url();
+    auto mainFrameURL = m_mainFrame ? m_mainFrame->url() : URL();
 
     m_uiClient->createNewPage(*this, WTFMove(originatingFrameInfo), WTFMove(request), WTFMove(windowFeatures), WTFMove(navigationActionData), [this, protectedThis = makeRef(*this), mainFrameURL, request, reply = WTFMove(reply)] (RefPtr<WebPageProxy> newPage) mutable {
         if (!newPage) {