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 6aabf786c74fc3c2979ebaf2c4bcde724c3023cb..41e2287a5de84a4db630a165d4b1d87f073293fe 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -91,6 +91,7 @@
 #include "content/public/browser/devtools_agent_host.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/download_url_parameters.h"
+#include "content/public/browser/guest_mode.h"
 #include "content/public/browser/invalidate_type.h"
 #include "content/public/browser/javascript_dialog_manager.h"
 #include "content/public/browser/load_notification_details.h"
@@ -1403,7 +1404,7 @@ void WebContentsImpl::DispatchBeforeUnload() {
 void WebContentsImpl::AttachToOuterWebContentsFrame(
     WebContents* outer_web_contents,
     RenderFrameHost* outer_contents_frame) {
-  CHECK(BrowserPluginGuestMode::UseCrossProcessFramesForGuests());
+  CHECK(guest_mode::IsCrossProcessFrameGuest(this));
   RenderFrameHostManager* render_manager = GetRenderManager();
 
   // When the WebContents being initialized has an opener, the  browser side
@@ -1559,8 +1560,7 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
 #endif
 
   if (!view_) {
-    if (browser_plugin_guest_ &&
-        BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+    if (guest_mode::IsCrossProcessFrameGuest(this)) {
       view_.reset(new WebContentsViewChildFrame(
           this, delegate, &render_view_host_delegate_view_));
     } else {
@@ -1570,7 +1570,7 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
   }
 
   if (browser_plugin_guest_ &&

[Charlie Reis, 2016/09/07 00:22:29]

Why does this still have the browser_plugin_guest_ null check when the previous
one doesn't?

[EhsanK, 2016/09/08 18:14:58]

The null check is inherent to the method call. So the call to
guest_mode::IsCrossProcessFrameGuest(wc) returns true if
1) |wc| is a guest (has |browser_plugin_guest_|
2) |wc| is OOPIF, i.e., we have the switch AND |wc| is not a
MimeHandlerViewGuest's web contents.

So when the method returns false, the web contents is either not guest or it is
a guest but not OOPIF.

[Charlie Reis, 2016/09/15 20:56:10]

That doesn't answer why line 1563 is missing the null check.  If it's needed
here, I would imagine it's needed there as well.

[EhsanK, 2016/09/21 21:34:53]

On line 1563, the call to guest_mode::IsCrossProcessFrameGuest(this) checks if
|this->browser_plugin_guest_|). So it is not needed to check again.

But here, when the method returns false we still don't know if it was because
our guest was not OOPIF, or we did not have guest at all. So we check for
|browser_plugin_guest_| to confirm that the former case is valid.

[Charlie Reis, 2016/09/21 22:18:21]

Oh, I see now.  Thanks.

-      !BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+      !guest_mode::IsCrossProcessFrameGuest(this)) {
     view_.reset(new WebContentsViewGuest(this, browser_plugin_guest_.get(),
                                          std::move(view_),
                                          &render_view_host_delegate_view_));
@@ -4175,13 +4175,12 @@ void WebContentsImpl::RemoveBrowserPluginEmbedder() {
 }
 
 WebContentsImpl* WebContentsImpl::GetOuterWebContents() {
-  if (BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
-    if (node_)
-      return node_->outer_web_contents();
-  } else {
-    if (GetBrowserPluginGuest())
-      return GetBrowserPluginGuest()->embedder_web_contents();
-  }
+  if (guest_mode::IsCrossProcessFrameGuest(this) && node_)
+    return node_->outer_web_contents();
+
+  if (browser_plugin_guest_)
+    return browser_plugin_guest_->embedder_web_contents();
+
   return nullptr;
 }
 
@@ -4611,7 +4610,7 @@ 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()) {
+        guest_mode::IsCrossProcessFrameGuest(source_web_contents)) {
       return;
     }