Move existing kSitePerProcess checks to a policy-oracle object

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 321aaeac80253402894b3e0a816d83a00f87001c..e46a2a677fc4154cbc0b581af0b8f2749e0c4a9d 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -72,7 +72,7 @@
 #include "content/public/browser/user_metrics.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_constants.h"
-#include "content/public/common/content_switches.h"
+#include "content/public/common/site_isolation_policy.h"
 #include "media/base/mime_util.h"
 #include "net/base/escape.h"
 #include "net/base/net_util.h"
@@ -753,8 +753,7 @@ void NavigationControllerImpl::LoadURLWithParams(const LoadURLParams& params) {
 
       // In --site-per-process, create an identical NavigationEntry with a
       // new FrameNavigationEntry for the target subframe.
-      if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-              switches::kSitePerProcess)) {
+      if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
         entry = GetLastCommittedEntry()->Clone();
         entry->SetPageID(-1);
         entry->AddOrUpdateFrameEntry(node, -1, -1, nullptr, params.url,
@@ -909,8 +908,7 @@ bool NavigationControllerImpl::RendererDidNavigate(
   NavigationEntryImpl* active_entry = GetLastCommittedEntry();
   active_entry->SetTimestamp(timestamp);
   active_entry->SetHttpStatusCode(params.http_status_code);
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSitePerProcess)) {
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
     // Update the frame-specific PageState.
     FrameNavigationEntry* frame_entry =
         active_entry->GetFrameEntry(rfh->frame_tree_node());
@@ -1290,8 +1288,7 @@ void NavigationControllerImpl::RendererDidNavigateNewSubframe(
     // take this out.
     //
     // Except for cross-process iframes; this doesn't work yet for them.
-    if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSitePerProcess)) {
+    if (!SiteIsolationPolicy::AreCrossProcessFramesPossible()) {
       NOTREACHED();
     }
 
@@ -1307,8 +1304,7 @@ void NavigationControllerImpl::RendererDidNavigateNewSubframe(
                                   << "that a last committed entry exists.";
 
   scoped_ptr<NavigationEntryImpl> new_entry;
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSitePerProcess)) {
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
     // Make sure new_entry takes ownership of frame_entry in a scoped_refptr.
     FrameNavigationEntry* frame_entry = new FrameNavigationEntry(
         rfh->frame_tree_node()->frame_tree_node_id(),
@@ -1363,8 +1359,7 @@ bool NavigationControllerImpl::RendererDidNavigateAutoSubframe(
     }
   }
 
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSitePerProcess)) {
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
     // This may be a "new auto" case where we add a new FrameNavigationEntry, or
     // it may be a "history auto" case where we update an existing one.
     NavigationEntryImpl* last_committed = GetLastCommittedEntry();
@@ -1817,8 +1812,7 @@ bool NavigationControllerImpl::NavigateToPendingEntryInternal(
   // In default Chrome, there are no subframe FrameNavigationEntries.  Either
   // navigate the main frame or use the main frame's FrameNavigationEntry to
   // tell the indicated frame where to go.
-  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSitePerProcess)) {
+  if (!SiteIsolationPolicy::UseSubframeNavigationEntries()) {
     FrameNavigationEntry* frame_entry = GetPendingEntry()->GetFrameEntry(root);
     FrameTreeNode* frame = root;
     int ftn_id = GetPendingEntry()->frame_tree_node_id();