[webui][ntp] Properly reference web contents

Previously, NewTabPageHandler was a content::WebContentsObserver.
However, we never associated it with a web contents. As a result, all
usages of web contents in the NTP handler were in fact a nullptr. This
CL fixes this by passing the correct web contents when creating the NTP
handler. Additionally, it removes content::WebContentsObserver as one of
the handler's interfaces as we are not observing any changes.

Change-Id: I4d79b726dbc7377f29b6f0630680bb13082a3c15
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2095785
Auto-Submit: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748473}

chrome/browser/ui/webui/new_tab_page/new_tab_page_handler.cc

@@ -63,16 +63,19 @@ NewTabPageHandler::NewTabPageHandler(
     mojo::PendingReceiver<new_tab_page::mojom::PageHandler>
         pending_page_handler,
     mojo::PendingRemote<new_tab_page::mojom::Page> pending_page,
-    Profile* profile)
+    Profile* profile,
+    content::WebContents* web_contents)
     : chrome_colors_service_(
           chrome_colors::ChromeColorsFactory::GetForProfile(profile)),
       instant_service_(InstantServiceFactory::GetForProfile(profile)),
       ntp_background_service_(
           NtpBackgroundServiceFactory::GetForProfile(profile)),
       page_{std::move(pending_page)},
-      receiver_{this, std::move(pending_page_handler)} {
+      receiver_{this, std::move(pending_page_handler)},
+      web_contents_(web_contents) {
   CHECK(instant_service_);
   CHECK(ntp_background_service_);
+  CHECK(web_contents_);
   instant_service_->AddObserver(this);
   ntp_background_service_->AddObserver(this);
   page_->SetTheme(MakeTheme(*instant_service_->GetInitializedNtpTheme()));
@@ -159,11 +162,11 @@ void NewTabPageHandler::GetChromeThemes(GetChromeThemesCallback callback) {
 }
 
 void NewTabPageHandler::ApplyDefaultTheme() {
-  chrome_colors_service_->ApplyDefaultTheme(web_contents());
+  chrome_colors_service_->ApplyDefaultTheme(web_contents_);
 }
 
 void NewTabPageHandler::ApplyAutogeneratedTheme(const SkColor& frame_color) {
-  chrome_colors_service_->ApplyAutogeneratedTheme(frame_color, web_contents());
+  chrome_colors_service_->ApplyAutogeneratedTheme(frame_color, web_contents_);
 }
 
 void NewTabPageHandler::ApplyChromeTheme(int32_t id) {
@@ -176,8 +179,7 @@ void NewTabPageHandler::ApplyChromeTheme(int32_t id) {
   if (result == end) {
     return;
   }
-  chrome_colors_service_->ApplyAutogeneratedTheme(result->color,
-                                                  web_contents());
+  chrome_colors_service_->ApplyAutogeneratedTheme(result->color, web_contents_);
 }
 
 void NewTabPageHandler::ConfirmThemeChanges() {

chrome/browser/ui/webui/new_tab_page/new_tab_page_handler.h

@@ -26,15 +26,19 @@ namespace chrome_colors {
 class ChromeColorsService;
 }  // namespace chrome_colors
 
-class NewTabPageHandler : public content::WebContentsObserver,
-                          public new_tab_page::mojom::PageHandler,
+namespace content {
+class WebContents;
+}  // namespace content
+
+class NewTabPageHandler : public new_tab_page::mojom::PageHandler,
                           public InstantServiceObserver,
                           public NtpBackgroundServiceObserver {
  public:
   NewTabPageHandler(mojo::PendingReceiver<new_tab_page::mojom::PageHandler>
                         pending_page_handler,
                     mojo::PendingRemote<new_tab_page::mojom::Page> pending_page,
-                    Profile* profile);
+                    Profile* profile,
+                    content::WebContents* web_contents);
   ~NewTabPageHandler() override;
 
   // new_tab_page::mojom::PageHandler:
@@ -82,6 +86,7 @@ class NewTabPageHandler : public content::WebContentsObserver,
   GetBackgroundImagesCallback background_images_callback_;
   mojo::Remote<new_tab_page::mojom::Page> page_;
   mojo::Receiver<new_tab_page::mojom::PageHandler> receiver_;
+  content::WebContents* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(NewTabPageHandler);
 };

chrome/browser/ui/webui/new_tab_page/new_tab_page_ui.cc

@@ -129,7 +129,8 @@ NewTabPageUI::NewTabPageUI(content::WebUI* web_ui)
     : ui::MojoWebUIController(web_ui, true),
       page_factory_receiver_(this),
       profile_(Profile::FromWebUI(web_ui)),
-      instant_service_(InstantServiceFactory::GetForProfile(profile_)) {
+      instant_service_(InstantServiceFactory::GetForProfile(profile_)),
+      web_contents_(web_ui->GetWebContents()) {
   content::WebUIDataSource::Add(profile_,
                                 CreateNewTabPageUiHtmlSource(profile_));
 
@@ -172,7 +173,8 @@ void NewTabPageUI::CreatePageHandler(
         pending_page_handler) {
   DCHECK(pending_page.is_valid());
   page_handler_ = std::make_unique<NewTabPageHandler>(
-      std::move(pending_page_handler), std::move(pending_page), profile_);
+      std::move(pending_page_handler), std::move(pending_page), profile_,
+      web_contents_);
 }
 
 void NewTabPageUI::NtpThemeChanged(const NtpTheme& theme) {

chrome/browser/ui/webui/new_tab_page/new_tab_page_ui.h

@@ -14,6 +14,7 @@
 #include "ui/webui/mojo_web_ui_controller.h"
 
 namespace content {
+class WebContents;
 class WebUI;
 }
 class GURL;
@@ -57,6 +58,7 @@ class NewTabPageUI : public ui::MojoWebUIController,
       page_factory_receiver_;
   Profile* profile_;
   InstantService* instant_service_;
+  content::WebContents* web_contents_;
 
   WEB_UI_CONTROLLER_TYPE_DECL();