Use WebContents instead of Browser to construct PermissionPrompt

chrome/browser/ui/cocoa/website_settings/permission_prompt_impl_views_mac.mm

 // 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_dialogs.h"
 #include "chrome/browser/ui/browser_window.h"
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #import "chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h"
@@ skipping 14 matching lines @@
 gfx::Point PermissionPromptImpl::GetAnchorPoint() {
   return gfx::ScreenPointFromNSPoint(
       [PermissionBubbleController getAnchorPointForBrowser:browser_]);
 }
 
 views::BubbleBorder::Arrow PermissionPromptImpl::GetAnchorArrow() {
   return views::BubbleBorder::TOP_LEFT;
 }
 
 // static
-std::unique_ptr<PermissionPrompt> PermissionPrompt::Create(Browser* browser) {
+std::unique_ptr<PermissionPrompt> PermissionPrompt::Create(
+    content::WebContents* web_contents) {
   if (chrome::ToolkitViewsWebUIDialogsEnabled())
-    return base::WrapUnique(new PermissionPromptImpl(browser));
-  return base::MakeUnique<PermissionBubbleCocoa>(browser);
+    return base::WrapUnique(new PermissionPromptImpl(web_contents));
+  return base::MakeUnique<PermissionBubbleCocoa>(web_contents);

[tapted, 2016/09/15 03:43:52]

Can this just be changed to pass
`chrome::FindBrowserWithWebContents(web_contents)`? Seems most of the other
Cocoa changes aren't required then. And since PermissionBubbleCocoa* retains a
weak pointer to Browser* (and it would be invalid to create permission prompts
for WebContents not in a Browser*, such as for packaged apps) this seems like
the more sensible API.

Also if the current UI code doesn't have a dependency on WebContents, and it
doesn't need one, we shouldn't be adding one.

Although I suppose the same could be said for the views-backed
PermissionPromptImpl.. Do the downstream things for android need changes to the
toolkit-views implementation too? (That is, is it enough to just change the two
desktop implementations of PermissionPrompt::Create(..) rather than the
platform-specific prompt implementations themselves, which assume they are on a
Browser*?)

[lshang, 2016/09/15 09:45:06]

Thanks for your detailed comment Trent! 

I think your suggestion is a good idea, which can make this CL much simpler,
also avoid causing any potential bugs on desktop due to use WebContents instead
of Browser for implementation.

Done.

 }