Remove GetRenderViewHost from CreateRenderFrameHost.

The current behaviour is not consistent with the name and the two
places that call CreateRenderFrameHost already have a call to
GetRenderViewHost in their logic.

This is a pre-factor for https://crrev.com/c/2084038/.

Change-Id: Ib9a16101373f0027cb712c955501360425056a97
Bug: 1059678
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089569
Commit-Queue: Fergal Daly <fergal@chromium.org>
Reviewed-by: Fergal Daly <fergal@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748727}

content/browser/frame_host/frame_tree.cc

@@ -388,11 +388,6 @@ scoped_refptr<RenderViewHostImpl> FrameTree::CreateRenderViewHost(
     int32_t main_frame_routing_id,
     int32_t widget_routing_id,
     bool swapped_out) {
-  scoped_refptr<RenderViewHostImpl> existing_rvh =
-      GetRenderViewHost(site_instance);
-  if (existing_rvh)
-    return existing_rvh;
-
   RenderViewHostImpl* rvh =
       static_cast<RenderViewHostImpl*>(RenderViewHostFactory::Create(
           site_instance, render_view_delegate_, render_widget_delegate_,

content/browser/frame_host/render_frame_host_manager.cc

@@ -2053,11 +2053,15 @@ RenderFrameHostManager::CreateRenderFrameHost(
 
   // Create a RVH for main frames, or find the existing one for subframes.
   FrameTree* frame_tree = frame_tree_node_->frame_tree();
-  scoped_refptr<RenderViewHostImpl> render_view_host;
+  scoped_refptr<RenderViewHostImpl> render_view_host =
+      frame_tree->GetRenderViewHost(site_instance);
+
   if (frame_tree_node_->IsMainFrame()) {
-    render_view_host = frame_tree->CreateRenderViewHost(
-        site_instance, view_routing_id, frame_routing_id, widget_routing_id,
-        false);
+    if (!render_view_host) {
+      render_view_host = frame_tree->CreateRenderViewHost(
+          site_instance, view_routing_id, frame_routing_id, widget_routing_id,
+          /*swapped_out=*/false);
+    }
     // TODO(avi): It's a bit bizarre that this logic lives here instead of in
     // CreateRenderFrame(). It turns out that FrameTree::CreateRenderViewHost
     // doesn't /always/ create a new RenderViewHost. It first tries to find an
@@ -2073,10 +2077,8 @@ RenderFrameHostManager::CreateRenderFrameHost(
       DCHECK_NE(view_routing_id, widget_routing_id);
       DCHECK_EQ(view_routing_id, render_view_host->GetRoutingID());
     }
-  } else {
-    render_view_host = frame_tree->GetRenderViewHost(site_instance);
-    CHECK(render_view_host);
   }
+  CHECK(render_view_host);
 
   return RenderFrameHostFactory::Create(
       site_instance, render_view_host, frame_tree->render_frame_delegate(),
@@ -2227,16 +2229,16 @@ void RenderFrameHostManager::CreateRenderFrameProxy(SiteInstance* instance) {
   if (!proxy) {
     // The RenderViewHost creates the page level structure in Blink. The first
     // object to depend on it is necessarily a main frame one.
-    CHECK(frame_tree_node_->frame_tree()->GetRenderViewHost(instance) ||
-          frame_tree_node_->IsMainFrame());
-
-    // Before creating a new RenderFrameProxyHost, ensure a RenderViewHost
-    // exists for |instance|, as it creates the page level structure in Blink.
     scoped_refptr<RenderViewHostImpl> render_view_host =
-        frame_tree_node_->frame_tree()->CreateRenderViewHost(
-            instance, MSG_ROUTING_NONE, MSG_ROUTING_NONE, MSG_ROUTING_NONE,
-            /*swapped_out=*/true);
-
+        frame_tree_node_->frame_tree()->GetRenderViewHost(instance);
+    CHECK(render_view_host || frame_tree_node_->IsMainFrame());
+    if (!render_view_host) {
+      // Before creating a new RenderFrameProxyHost, ensure a RenderViewHost
+      // exists for |instance|, as it creates the page level structure in Blink.
+      render_view_host = frame_tree_node_->frame_tree()->CreateRenderViewHost(
+          instance, MSG_ROUTING_NONE, MSG_ROUTING_NONE, MSG_ROUTING_NONE,
+          /*swapped_out=*/true);
+    }
     proxy = CreateRenderFrameProxyHost(instance, std::move(render_view_host));
   }