Permission prompts show in the top-left corner in fullscreen mode.

chrome/browser/ui/views/website_settings/permissions_bubble_view_views.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/views/exclusive_access_bubble_views.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/frame/top_container_view.h"
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
 #include "chrome/browser/ui/views/location_bar/location_icon_view.h"
 #include "chrome/browser/ui/views/website_settings/permissions_bubble_view.h"
 #include "ui/gfx/geometry/point.h"
+#include "ui/gfx/geometry/vector2d.h"
 
 // The Views browser implementation of PermissionBubbleViewViews'
 // anchor methods. Views browsers have a native View to anchor the bubble to,
 // which these functions provide.
 
+// Left margin for the bubble when anchored to the top of the screen in
+// fullscreen mode.
+const int kFullscreenLeftMargin = 40;
+
 views::View* PermissionBubbleViewViews::GetAnchorView() {
   BrowserView* browser_view = BrowserView::GetBrowserViewForBrowser(browser_);
 
   if (browser_->SupportsWindowFeature(Browser::FEATURE_LOCATIONBAR))
     return browser_view->GetLocationBarView()->location_icon_view();
 
-  return browser_view->top_container();
+  // Fall back to GetAnchorPoint().
+  return nullptr;
 }
 
 gfx::Point PermissionBubbleViewViews::GetAnchorPoint() {
-  return gfx::Point();
+  BrowserView* browser_view = BrowserView::GetBrowserViewForBrowser(browser_);
+  // Get position in view (taking RTL displays into account).
+  int x_within_browser_view =
+      browser_view->GetMirroredXInView(kFullscreenLeftMargin);
+  // Get position in screen (taking browser view origin into account, which may
+  // not be 0,0 if there are multiple displays).
+  gfx::Point browser_view_origin = browser_view->GetBoundsInScreen().origin();
+  return browser_view_origin + gfx::Vector2d(x_within_browser_view, 0);
 }
 
 views::BubbleBorder::Arrow PermissionBubbleViewViews::GetAnchorArrow() {
-  if (browser_->SupportsWindowFeature(Browser::FEATURE_LOCATIONBAR))
-    return views::BubbleBorder::TOP_LEFT;
-  return views::BubbleBorder::NONE;
+  return views::BubbleBorder::TOP_LEFT;
 }
 
 // static
 std::unique_ptr<PermissionBubbleView> PermissionBubbleView::Create(
     Browser* browser) {
   return base::WrapUnique(new PermissionBubbleViewViews(browser));
 }