Avoid URL allocation for GetContentSettingFromRules fast path

chrome/renderer/content_settings_observer.cc

 // Copyright (c) 2012 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 "chrome/renderer/content_settings_observer.h"
 
 #include "chrome/common/render_messages.h"
 #include "chrome/common/ssl_insecure_content.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/renderer/document_state.h"
@@ skipping 39 matching lines @@
   // The |top_origin| is unique ("null") e.g., for file:// URLs. Use the
   // document URL as the primary URL in those cases.
   // TODO(alexmos): This is broken for --site-per-process, since top() can be a
   // WebRemoteFrame which does not have a document(), and the WebRemoteFrame's
   // URL is not replicated.  See https://crbug.com/628759.
   if (top_origin.unique() && frame->top()->isWebLocalFrame())
     return frame->top()->document().url();
   return top_origin.GetURL();
 }
 
+// Allow passing both WebURL and GURL here, so that we can early return without
+// allocating a new backing string if only the default rule matches.
+template <typename URL>
 ContentSetting GetContentSettingFromRules(
     const ContentSettingsForOneType& rules,
     const WebFrame* frame,
-    const GURL& secondary_url) {
+    const URL& secondary_url) {
   ContentSettingsForOneType::const_iterator it;
   // If there is only one rule, it's the default rule and we don't need to match
   // the patterns.
   if (rules.size() == 1) {
     DCHECK(rules[0].primary_pattern == ContentSettingsPattern::Wildcard());
     DCHECK(rules[0].secondary_pattern == ContentSettingsPattern::Wildcard());
     return rules[0].setting;
   }
   const GURL& primary_url = GetOriginOrURL(frame);
+  const GURL& secondary_gurl = secondary_url;
   for (it = rules.begin(); it != rules.end(); ++it) {
     if (it->primary_pattern.Matches(primary_url) &&
-        it->secondary_pattern.Matches(secondary_url)) {
+        it->secondary_pattern.Matches(secondary_gurl)) {
       return it->setting;
     }
   }
   NOTREACHED();
   return CONTENT_SETTING_DEFAULT;
 }
 
 }  // namespace
 
 ContentSettingsObserver::ContentSettingsObserver(
@@ skipping 158 matching lines @@
                                          const WebURL& image_url) {
   bool allow = enabled_per_settings;
   if (enabled_per_settings) {
     if (is_interstitial_page_)
       return true;
 
     if (IsWhitelistedForContentSettings())
       return true;
 
     if (content_setting_rules_) {
-      GURL secondary_url(image_url);
-      allow =
-          GetContentSettingFromRules(content_setting_rules_->image_rules,
-                                     render_frame()->GetWebFrame(),
-                                     secondary_url) != CONTENT_SETTING_BLOCK;
+      allow = GetContentSettingFromRules(content_setting_rules_->image_rules,
+                                         render_frame()->GetWebFrame(),
+                                         image_url) != CONTENT_SETTING_BLOCK;
     }
   }
   if (!allow)
     DidBlockContentType(CONTENT_SETTINGS_TYPE_IMAGES);
   return allow;
 }
 
 bool ContentSettingsObserver::allowIndexedDB(const WebString& name,
                                              const WebSecurityOrigin& origin) {
   WebFrame* frame = render_frame()->GetWebFrame();
@@ skipping 44 matching lines @@
     const blink::WebURL& script_url) {
   if (!enabled_per_settings)
     return false;
   if (is_interstitial_page_)
     return true;
 
   bool allow = true;
   if (content_setting_rules_) {
     ContentSetting setting =
         GetContentSettingFromRules(content_setting_rules_->script_rules,
-                                   render_frame()->GetWebFrame(),
-                                   GURL(script_url));
+                                   render_frame()->GetWebFrame(), script_url);
     allow = setting != CONTENT_SETTING_BLOCK;
   }
   return allow || IsWhitelistedForContentSettings();
 }
 
 bool ContentSettingsObserver::allowStorage(bool local) {
   WebFrame* frame = render_frame()->GetWebFrame();
   if (frame->getSecurityOrigin().isUnique() ||
       frame->top()->getSecurityOrigin().isUnique())
     return false;
@@ skipping 194 matching lines @@
 
   // If the scheme is file:, an empty file name indicates a directory listing,
   // which requires JavaScript to function properly.
   if (base::EqualsASCII(protocol, url::kFileScheme)) {
     return document_url.SchemeIs(url::kFileScheme) &&
            document_url.ExtractFileName().empty();
   }
 
   return false;
 }