MD Settings: avoid double pref observation on Startup Pages

chrome/browser/ui/webui/settings/md_settings_ui.cc

Index: chrome/browser/ui/webui/settings/md_settings_ui.cc
diff --git a/chrome/browser/ui/webui/settings/md_settings_ui.cc b/chrome/browser/ui/webui/settings/md_settings_ui.cc
index 592759e9a1e8281c273a07995e607cdac3ead029..5718b6540c022e940986d27788a5b100841f9a11 100644
--- a/chrome/browser/ui/webui/settings/md_settings_ui.cc
+++ b/chrome/browser/ui/webui/settings/md_settings_ui.cc
@@ -123,12 +123,16 @@ MdSettingsUI::MdSettingsUI(content::WebUI* web_ui)
 MdSettingsUI::~MdSettingsUI() {
 }
 
-void MdSettingsUI::AddSettingsPageUIHandler(
-    content::WebUIMessageHandler* handler_raw) {
-  scoped_ptr<content::WebUIMessageHandler> handler(handler_raw);
-  DCHECK(handler.get());
+void MdSettingsUI::RenderViewReused(
+    content::RenderViewHost* /*render_view_host*/) {
+  for (size_t i = 0; i < handlers_.size(); ++i)
+    handlers_[i]->RenderViewReused();

[dschuyler, 2016/03/10 21:49:49]

How about this instead?
for (auto handler : handlers_)
  handler->RenderViewReused();

[Dan Beam, 2016/03/11 00:07:12]

Done.

+}
 
-  web_ui()->AddMessageHandler(handler.release());
+void MdSettingsUI::AddSettingsPageUIHandler(SettingsPageUIHandler* handler) {
+  DCHECK(handler);

[dschuyler, 2016/03/10 21:49:49]

Would it be bad to have the same handler added twice?
Is that worth DCHECK'ing?

[Dan Beam, 2016/03/11 00:07:11]

Done.

+  handlers_.push_back(handler);
+  web_ui()->AddMessageHandler(handler);  // |handler| is owned by |web_ui()|.
 }
 
 void MdSettingsUI::DidStartProvisionalLoadForFrame(