Make WebContents::GetOuterWebContents() const.

Change-Id: I60d5a327f7f0ad22dccdbdcbe15dbfaf89f98918
Reviewed-on: https://chromium-review.googlesource.com/c/1302493Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Commit-Queue: Lucas Gadani <lfg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603972}

content/browser/web_contents/web_contents_impl.cc

@@ -5417,7 +5417,7 @@ void WebContentsImpl::RemoveBrowserPluginEmbedder() {
     browser_plugin_embedder_.reset();
 }
 
-WebContentsImpl* WebContentsImpl::GetOuterWebContents() {
+WebContentsImpl* WebContentsImpl::GetOuterWebContents() const {
   if (GuestMode::IsCrossProcessFrameGuest(this))
     return node_.outer_web_contents();
 

content/browser/web_contents/web_contents_impl.h

@@ -360,7 +360,7 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
   void AttachToOuterWebContentsFrame(
       std::unique_ptr<WebContents> current_web_contents,
       RenderFrameHost* outer_contents_frame) override;
-  WebContentsImpl* GetOuterWebContents() override;
+  WebContentsImpl* GetOuterWebContents() const override;
   WebContentsImpl* GetOutermostWebContents() override;
   void DidChangeVisibleSecurityState() override;
   void NotifyPreferencesChanged() override;

content/public/browser/guest_mode.cc

@@ -14,9 +14,10 @@
 namespace content {
 
 // static
-bool GuestMode::IsCrossProcessFrameGuest(WebContents* web_contents) {
+bool GuestMode::IsCrossProcessFrameGuest(const WebContents* web_contents) {
   BrowserPluginGuest* browser_plugin_guest =
-      static_cast<WebContentsImpl*>(web_contents)->GetBrowserPluginGuest();
+      static_cast<const WebContentsImpl*>(web_contents)
+          ->GetBrowserPluginGuest();
 
   if (!browser_plugin_guest ||
       !browser_plugin_guest->can_use_cross_process_frames()) {

content/public/browser/guest_mode.h

@@ -16,7 +16,7 @@ class CONTENT_EXPORT GuestMode {
  public:
   // Returns true if |web_contents| is an inner WebContents based on cross
   // process frames.
-  static bool IsCrossProcessFrameGuest(WebContents* web_contents);
+  static bool IsCrossProcessFrameGuest(const WebContents* web_contents);
 
  private:
   GuestMode();

content/public/browser/web_contents.h

@@ -535,7 +535,7 @@ class WebContents : public PageNavigator,
 
   // Returns the outer WebContents of this WebContents if any.
   // Otherwise, return nullptr.
-  virtual WebContents* GetOuterWebContents() = 0;
+  virtual WebContents* GetOuterWebContents() const = 0;
 
   // Returns the root WebContents of the WebContents tree. Always returns
   // non-null value.