Force MimeHandlerView to always use BrowserPlugin

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 62dfcec24f0af2a1ddda3258e25047494a32db7a..77f1cab87ee54d01aac9a74aba5faaf7a66caa64 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1538,6 +1538,7 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
 
   if (!view_) {
     if (browser_plugin_guest_ &&
+        !browser_plugin_guest_->IsMimeHandlerViewGuest() &&
         BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
       view_.reset(new WebContentsViewChildFrame(
           this, delegate, &render_view_host_delegate_view_));
@@ -1548,7 +1549,8 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
   }
 
   if (browser_plugin_guest_ &&
-      !BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+      (!BrowserPluginGuestMode::UseCrossProcessFramesForGuests() ||
+       browser_plugin_guest_->IsMimeHandlerViewGuest())) {
     view_.reset(new WebContentsViewGuest(this, browser_plugin_guest_.get(),
                                          std::move(view_),
                                          &render_view_host_delegate_view_));
@@ -4581,7 +4583,9 @@ void WebContentsImpl::EnsureOpenerProxiesExist(RenderFrameHost* source_rfh) {
     // then we should not create a RenderView. AttachToOuterWebContentsFrame()
     // already created a RenderFrameProxyHost for that purpose.
     if (GetBrowserPluginEmbedder() &&
-        BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+        BrowserPluginGuestMode::UseCrossProcessFramesForGuests() &&
+        !source_web_contents->GetBrowserPluginGuest()
+             ->IsMimeHandlerViewGuest()) {
       return;
     }
 
@@ -4984,7 +4988,9 @@ RenderFrameHostManager* WebContentsImpl::GetRenderManager() const {
 }
 
 WebContentsImpl* WebContentsImpl::GetOuterWebContents() {
-  if (BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+  if (BrowserPluginGuestMode::UseCrossProcessFramesForGuests() &&
+      (!GetBrowserPluginGuest() ||

[lfg, 2016/07/20 19:49:57]

Why do you need the null check?

And you can use browser_plugin_guest_ directly, like the other functions around
here.

[EhsanK, 2016/07/20 20:49:19]

|browser_plugin_guest_| is null when we are in an outer WebContents. When in an
inner WebContents, we also want to make sure that the guest is
MimeHandlerViewGuest.

Following your suggestion, I am using |browser_plugin_guest_| rather than
GetBrowserPluginGuest(). Thanks!

[lfg, 2016/07/20 21:05:34]

Acknowledged.

+       !GetBrowserPluginGuest()->IsMimeHandlerViewGuest())) {
     if (node_)
       return node_->outer_web_contents();
   } else {