webui: Change slightly how the scale-factor gets parsed from a URL.

chrome/browser/ui/webui/web_ui_util.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/browser/ui/webui/web_ui_util.h"
 
 #include <vector>
 
 #include "base/base64.h"
 #include "base/logging.h"
@@ skipping 61 matching lines @@
   CHECK(args->GetDouble(start_index++, &button));
   CHECK(args->GetBoolean(start_index++, &alt_key));
   CHECK(args->GetBoolean(start_index++, &ctrl_key));
   CHECK(args->GetBoolean(start_index++, &meta_key));
   CHECK(args->GetBoolean(start_index++, &shift_key));
   return disposition_utils::DispositionFromClick(button == 1.0, alt_key,
                                                  ctrl_key, meta_key, shift_key);
 
 }
 
-ui::ScaleFactor ParseScaleFactor(const base::StringPiece& identifier) {
+bool ParseScaleFactor(const base::StringPiece& identifier,
+                      ui::ScaleFactor* scale_factor) {
+  *scale_factor = ui::SCALE_FACTOR_NONE;
   for (size_t i = 0; i < arraysize(kScaleFactorMap); i++) {
-    if (identifier == kScaleFactorMap[i].name)
-      return kScaleFactorMap[i].scale_factor;
+    if (identifier == kScaleFactorMap[i].name) {
+      *scale_factor = kScaleFactorMap[i].scale_factor;
+      return true;
+    }
   }
-  return ui::SCALE_FACTOR_NONE;
+  return false;
 }
 
 void ParsePathAndScale(const GURL& url,
                        std::string* path,
                        ui::ScaleFactor* scale_factor) {
   *path = net::UnescapeURLComponent(url.path().substr(1),
                                     (net::UnescapeRule::URL_SPECIAL_CHARS |
                                      net::UnescapeRule::SPACES));
   if (scale_factor)
     *scale_factor = ui::SCALE_FACTOR_100P;
 
   // Detect and parse resource string ending in @<scale>x.
   std::size_t pos = path->rfind('@');
   if (pos != std::string::npos) {
     base::StringPiece stripped_path(*path);
-    if (scale_factor) {
-      *scale_factor = ParseScaleFactor(stripped_path.substr(
-          pos + 1, stripped_path.length() - pos - 1));
+    ui::ScaleFactor factor;
+
+    if (ParseScaleFactor(stripped_path.substr(
+            pos + 1, stripped_path.length() - pos - 1), &factor)) {
+      // Strip scale factor specification from path.
+      stripped_path.remove_suffix(stripped_path.length() - pos);
+      stripped_path.CopyToString(path);
     }
-    // Strip scale factor specification from path.
-    stripped_path.remove_suffix(stripped_path.length() - pos);
-    stripped_path.CopyToString(path);
+    if (scale_factor)
+      *scale_factor = factor;
   }
 }
 
 }  // namespace web_ui_util