Remove variable shadowing in blink/frame

In an effort to reduce or even ban variable shadowing, this renames a
couple of variables. I'm interested in prohibiting shadowing because I
think it might prevent potential jumbo problems.

The exact error this avoids is:
third_party/blink/renderer/core/frame/frame_serializer.cc:301:12: error: declaration shadows a local variable [-Werror,-Wshadow]
      KURL url =
           ^
third_party/blink/renderer/core/frame/frame_serializer.cc:261:8: note: previous declaration is here
  KURL url = document.Url();
       ^
third_party/blink/renderer/core/frame/frame_serializer.cc:307:14: error: declaration shadows a local variable [-Werror,-Wshadow]
        KURL url = input->Src();
             ^
third_party/blink/renderer/core/frame/frame_serializer.cc:261:8: note: previous declaration is here
  KURL url = document.Url();
       ^
third_party/blink/renderer/core/frame/frame_serializer.cc:313:14: error: declaration shadows a local variable [-Werror,-Wshadow]
        KURL url =
             ^
third_party/blink/renderer/core/frame/frame_serializer.cc:261:8: note: previous declaration is here
  KURL url = document.Url();
       ^
third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc:110:14: error: declaration shadows a local variable [-Werror,-Wshadow]
      String uma_name = uma_percentage_preamble;
             ^
third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc:94:10: note: previous declaration is here
    auto uma_name = uma_preamble;
         ^
third_party/blink/renderer/core/frame/rotation_viewport_anchor.cc:52:21: error: declaration shadows a local variable [-Werror,-Wshadow]
    HitTestLocation location(point + point_offset);
                    ^
third_party/blink/renderer/core/frame/rotation_viewport_anchor.cc:30:19: note: previous declaration is here
  HitTestLocation location(point);
                  ^

Bug: 923510
Change-Id: I9bd46559f31e6b3fdb412cf7787b764ae84c775b
Reviewed-on: https://chromium-review.googlesource.com/c/1494659
Commit-Queue: Daniel Bratell <bratell@opera.com>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Auto-Submit: Daniel Bratell <bratell@opera.com>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#636453}
diff --git a/third_party/blink/renderer/core/frame/frame_serializer.cc b/third_party/blink/renderer/core/frame/frame_serializer.cc
index cc15dd0..de81b2a 100644
--- a/third_party/blink/renderer/core/frame/frame_serializer.cc
+++ b/third_party/blink/renderer/core/frame/frame_serializer.cc
@@ -298,21 +298,21 @@
     }
 
     if (const auto* image = ToHTMLImageElementOrNull(element)) {
-      KURL url =
+      KURL image_url =
           document.CompleteURL(image->getAttribute(html_names::kSrcAttr));
       ImageResourceContent* cached_image = image->CachedImage();
-      AddImageToResources(cached_image, url);
+      AddImageToResources(cached_image, image_url);
     } else if (const auto* input = ToHTMLInputElementOrNull(element)) {
       if (input->type() == input_type_names::kImage && input->ImageLoader()) {
-        KURL url = input->Src();
+        KURL image_url = input->Src();
         ImageResourceContent* cached_image = input->ImageLoader()->GetContent();
-        AddImageToResources(cached_image, url);
+        AddImageToResources(cached_image, image_url);
       }
     } else if (const auto* link = ToHTMLLinkElementOrNull(element)) {
       if (CSSStyleSheet* sheet = link->sheet()) {
-        KURL url =
+        KURL sheet_url =
             document.CompleteURL(link->getAttribute(html_names::kHrefAttr));
-        SerializeCSSStyleSheet(*sheet, url);
+        SerializeCSSStyleSheet(*sheet, sheet_url);
       }
     } else if (const auto* style = ToHTMLStyleElementOrNull(element)) {
       if (CSSStyleSheet* sheet = style->sheet())
diff --git a/third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc b/third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc
index 152ba1b..feee735 100644
--- a/third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc
+++ b/third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc
@@ -91,7 +91,7 @@
     absolute_record.average_metric_name = metric_name;
     absolute_record.average_metric_name.append(".Average");
     absolute_record.reset();
-    auto uma_name = uma_preamble;
+    String uma_name = uma_preamble;
     uma_name.append(metric_name);
     uma_name.append(uma_postscript);
     absolute_record.uma_counter.reset(
@@ -107,13 +107,13 @@
     percentage_record.average_metric_name.append(".AverageRatio");
     percentage_record.reset();
     for (auto bucket_substring : threshold_substrings) {
-      String uma_name = uma_percentage_preamble;
-      uma_name.append(metric_name);
-      uma_name.append(uma_percentage_postscript);
-      uma_name.append(bucket_substring);
+      String uma_percentage_name = uma_percentage_preamble;
+      uma_percentage_name.append(metric_name);
+      uma_percentage_name.append(uma_percentage_postscript);
+      uma_percentage_name.append(bucket_substring);
       percentage_record.uma_counters_per_bucket.push_back(
-          std::make_unique<CustomCountHistogram>(uma_name.Utf8().data(), 0,
-                                                 10000000, 50));
+          std::make_unique<CustomCountHistogram>(
+              uma_percentage_name.Utf8().data(), 0, 10000000, 50));
     }
   }
 }
diff --git a/third_party/blink/renderer/core/frame/rotation_viewport_anchor.cc b/third_party/blink/renderer/core/frame/rotation_viewport_anchor.cc
index c87d81d..fa7863d 100644
--- a/third_party/blink/renderer/core/frame/rotation_viewport_anchor.cc
+++ b/third_party/blink/renderer/core/frame/rotation_viewport_anchor.cc
@@ -49,10 +49,11 @@
   if (node_size.Width() * node_size.Height() > max_node_area) {
     IntSize point_offset = view_rect.Size();
     point_offset.Scale(kViewportAnchorRelativeEpsilon);
-    HitTestLocation location(point + point_offset);
+    HitTestLocation alternative_location(point + point_offset);
     node = event_handler
-               .HitTestResultAtLocation(location, HitTestRequest::kReadOnly |
-                                                      HitTestRequest::kActive)
+               .HitTestResultAtLocation(
+                   alternative_location,
+                   HitTestRequest::kReadOnly | HitTestRequest::kActive)
                .InnerNode();
   }