Avoid GURL allocations/copies/frees in RenderFrameImpl::willSendRequest

chrome/renderer/extensions/chrome_extensions_renderer_client.cc

Index: chrome/renderer/extensions/chrome_extensions_renderer_client.cc
diff --git a/chrome/renderer/extensions/chrome_extensions_renderer_client.cc b/chrome/renderer/extensions/chrome_extensions_renderer_client.cc
index 141bf76e929755914211405173ec293b5314dad3..54947da974591656d81dada83abd4165e0d21fdd 100644
--- a/chrome/renderer/extensions/chrome_extensions_renderer_client.cc
+++ b/chrome/renderer/extensions/chrome_extensions_renderer_client.cc
@@ -210,16 +210,16 @@ bool ChromeExtensionsRendererClient::AllowPopup() {
 bool ChromeExtensionsRendererClient::WillSendRequest(
     blink::WebFrame* frame,
     ui::PageTransition transition_type,
-    const GURL& url,
+    const blink::WebURL& url,
     GURL* new_url) {
-  if (url.SchemeIs(extensions::kExtensionScheme) &&
-      !resource_request_policy_->CanRequestResource(url, frame,
+  if (url.protocolIs(extensions::kExtensionScheme) &&

[Devlin, 2016/10/31 15:17:39]

My url spec knowledge is limited, so I might be completely off base, but I
thought there were actually some cases when scheme and protocol were *not* the
same thing (even though they almost always are).  e.g. with the news scheme, I
thought the protocol was nntp.

Looking into the implementation for protocolIs(), it looks like we even just
compare schemes there, so maybe this is all well and good.  But I wonder if it's
worth a comment explaining why this is safe explicitly for the extension scheme?

[Charlie Harrison, 2016/10/31 15:46:13]

Hm yeah I think "protocol" here is a misnomer, as we're really accessing the
scheme part of the URL. In that case I would not want to add a comment saying
that the protocol and scheme for extensions are the same, because it could
possibly spread misinformation that they would ever be different in the code.

I can get in touch with KURL owners to see about this discrepancy.

[Devlin, 2016/10/31 16:00:57]

sgtm; I'm fine with this for now since it *is* safe for extension schemes. 
Lemme know what they say. :)

[Charlie Harrison, 2016/10/31 16:37:34]

I filed crbug.com/660875 asking for owners advice here, and cc'd you.

+      !resource_request_policy_->CanRequestResource(GURL(url), frame,
                                                     transition_type)) {
     *new_url = GURL(chrome::kExtensionInvalidRequestURL);
     return true;
   }
 
-  if (url.SchemeIs(extensions::kExtensionResourceScheme) &&
+  if (url.protocolIs(extensions::kExtensionResourceScheme) &&
       !resource_request_policy_->CanRequestExtensionResourceScheme(url,
                                                                    frame)) {
     *new_url = GURL(chrome::kExtensionResourceInvalidRequestURL);