Fix crash when tab with media dragged to new window

Creating a new window for a tab playing media shows the medial toolbar
button immediately. With a recent change, it would then attempt to get
the window's BrowserView. But BrowserView::GetBrowserViewForBrowser()
returns nullptr when called during BrowserView construction resulting
in a crash.

This CL changes MediaToolbarButtonView to take the BrowserView on
construction instead.

Fixed: 1130921, 1130897
Change-Id: Ica879fe9825c4ef1af2789169bffb49da28370b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2423551Reviewed-by: Abigail Klein <abigailbklein@google.com>
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809365}

chrome/browser/ui/views/global_media_controls/media_toolbar_button_view.cc

@@ -30,11 +30,12 @@
 #include "ui/views/animation/ink_drop.h"
 #include "ui/views/controls/button/button_controller.h"
 
-MediaToolbarButtonView::MediaToolbarButtonView(const Browser* browser)
+MediaToolbarButtonView::MediaToolbarButtonView(BrowserView* browser_view)
     : ToolbarButton(this),
-      service_(
-          MediaNotificationServiceFactory::GetForProfile(browser->profile())),
-      browser_(browser) {
+      browser_(browser_view->browser()),
+      service_(MediaNotificationServiceFactory::GetForProfile(
+          browser_view->browser()->profile())),
+      feature_promo_controller_(browser_view->feature_promo_controller()) {
   GlobalMediaControlsInProductHelp* global_media_controls_in_product_help =
       GlobalMediaControlsInProductHelpFactory::GetForProfile(
           browser_->profile());
@@ -162,14 +163,10 @@ void MediaToolbarButtonView::OnPromoEnded() {
 }
 
 void MediaToolbarButtonView::EnsurePromoController() {
-  if (!promo_controller_) {
-    promo_controller_ = std::make_unique<GlobalMediaControlsPromoController>(
-        this, browser_->profile());
-    AddObserver(promo_controller_.get());
-  }
+  if (promo_controller_)
+    return;
 
-  if (!feature_promo_controller_) {
-    feature_promo_controller_ = BrowserView::GetBrowserViewForBrowser(browser_)
-                                    ->feature_promo_controller();
-  }
+  promo_controller_ = std::make_unique<GlobalMediaControlsPromoController>(
+      this, browser_->profile());
+  AddObserver(promo_controller_.get());
 }

chrome/browser/ui/views/global_media_controls/media_toolbar_button_view.h

@@ -10,6 +10,7 @@
 #include "chrome/browser/ui/views/toolbar/toolbar_button.h"
 
 class Browser;
+class BrowserView;
 class FeaturePromoControllerViews;
 class GlobalMediaControlsPromoController;
 class MediaNotificationService;
@@ -23,7 +24,7 @@ class MediaToolbarButtonView : public ToolbarButton,
                                public MediaToolbarButtonControllerDelegate,
                                public views::ButtonListener {
  public:
-  explicit MediaToolbarButtonView(const Browser* browser);
+  explicit MediaToolbarButtonView(BrowserView* browser_view);
   ~MediaToolbarButtonView() override;
 
   void AddObserver(MediaToolbarButtonObserver* observer);
@@ -65,18 +66,20 @@ class MediaToolbarButtonView : public ToolbarButton,
   void InformIPHOfButtonEnabled();
   void InformIPHOfButtonDisabledorHidden();
 
-  // Shows the in-product help bubble.
-  std::unique_ptr<GlobalMediaControlsPromoController> promo_controller_;
+  const Browser* const browser_;
+
+  MediaNotificationService* const service_;
 
   // The window's IPH promo controller.
-  FeaturePromoControllerViews* feature_promo_controller_ = nullptr;
+  FeaturePromoControllerViews* const feature_promo_controller_;
+
+  // Shows the in-product help bubble.
+  std::unique_ptr<GlobalMediaControlsPromoController> promo_controller_;
 
   // True if the in-product help bubble is currently showing.
   bool is_promo_showing_ = false;
 
-  MediaNotificationService* const service_;
   std::unique_ptr<MediaToolbarButtonController> controller_;
-  const Browser* const browser_;
 
   base::ObserverList<MediaToolbarButtonObserver> observers_;
 

chrome/browser/ui/views/toolbar/toolbar_view.cc

@@ -228,7 +228,7 @@ void ToolbarView::Init() {
 
   std::unique_ptr<MediaToolbarButtonView> media_button;
   if (base::FeatureList::IsEnabled(media::kGlobalMediaControls)) {
-    media_button = std::make_unique<MediaToolbarButtonView>(browser_);
+    media_button = std::make_unique<MediaToolbarButtonView>(browser_view_);
   }
 
   std::unique_ptr<ToolbarAccountIconContainerView>