Remove some variable shadowing in blink/core

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

The exact warnings this prevents is:

third_party/blink/renderer/core/fileapi/file_reader_loader.cc:358:16: error: declaration shadows a local variable [-Werror,-Wshadow]
    MojoResult result = consumer_handle_->BeginReadData(
               ^
third_party/blink/renderer/core/fileapi/file_reader_loader.cc:346:54: note: previous declaration is here
void FileReaderLoader::OnDataPipeReadable(MojoResult result) {
                                                     ^

third_party/blink/renderer/core/aom/accessible_node.cc:288:16: error: declaration shadows a local variable [-Werror,-Wshadow]
      Element* element = accessible_node->element();
               ^
third_party/blink/renderer/core/aom/accessible_node.cc:278:43: note: previous declaration is here
bool AccessibleNode::GetProperty(Element* element,
                                          ^

third_party/blink/renderer/core/invisible_dom/invisible_dom.cc:43:16: error: declaration shadows a local variable [-Werror,-Wshadow]
    for (Node& node : FlatTreeTraversal::AncestorsOf(node)) {
               ^
third_party/blink/renderer/core/invisible_dom/invisible_dom.cc:40:14: note: previous declaration is here
  for (Node& node : range.Nodes()) {
             ^

third_party/blink/renderer/core/loader/frame_loader.cc:892:10: error: declaration shadows a local variable [-Werror,-Wshadow]
    auto request = mojo::MakeRequest(&navigation_initiator);
         ^
third_party/blink/renderer/core/loader/frame_loader.cc:798:20: note: previous declaration is here
  FrameLoadRequest request(passed_request);
                   ^

third_party/blink/renderer/core/script/modulator.cc:52:20: error: declaration shadows a local variable [-Werror,-Wshadow]
  } else if (auto* scope = DynamicTo<WorkerGlobalScope>(execution_context)) {
                   ^
third_party/blink/renderer/core/script/modulator.cc:45:20: note: previous declaration is here
  } else if (auto* scope = DynamicTo<WorkletGlobalScope>(execution_context)) {
                   ^

Bug: 923510
Change-Id: I82659c403eb15b4f676d24b97414bfbbced9d701
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1508517
Commit-Queue: Daniel Bratell <bratell@opera.com>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#638662}

third_party/blink/renderer/core/aom/accessible_node.cc

@@ -285,9 +285,8 @@ bool AccessibleNode::GetProperty(Element* element,
   for (wtf_size_t i = 0; i < node_list->length(); ++i) {
     AccessibleNode* accessible_node = node_list->item(i);
     if (accessible_node) {
-      Element* element = accessible_node->element();
-      if (element)
-        targets.push_back(element);
+      if (Element* target_element = accessible_node->element())
+        targets.push_back(target_element);
     }
   }
 

third_party/blink/renderer/core/fileapi/file_reader_loader.cc

@@ -355,17 +355,18 @@ void FileReaderLoader::OnDataPipeReadable(MojoResult result) {
   while (true) {
     uint32_t num_bytes;
     const void* buffer;
-    MojoResult result = consumer_handle_->BeginReadData(
+    MojoResult pipe_result = consumer_handle_->BeginReadData(
         &buffer, &num_bytes, MOJO_READ_DATA_FLAG_NONE);
-    if (result == MOJO_RESULT_SHOULD_WAIT) {
+    if (pipe_result == MOJO_RESULT_SHOULD_WAIT) {
       if (!IsSyncLoad())
         return;
 
-      result = mojo::Wait(consumer_handle_.get(), MOJO_HANDLE_SIGNAL_READABLE);
-      if (result == MOJO_RESULT_OK)
+      pipe_result =
+          mojo::Wait(consumer_handle_.get(), MOJO_HANDLE_SIGNAL_READABLE);
+      if (pipe_result == MOJO_RESULT_OK)
         continue;
     }
-    if (result == MOJO_RESULT_FAILED_PRECONDITION) {
+    if (pipe_result == MOJO_RESULT_FAILED_PRECONDITION) {
       // Pipe closed.
       if (!received_all_data_) {
         Failed(FileErrorCode::kNotReadableErr,
@@ -373,7 +374,7 @@ void FileReaderLoader::OnDataPipeReadable(MojoResult result) {
       }
       return;
     }
-    if (result != MOJO_RESULT_OK) {
+    if (pipe_result != MOJO_RESULT_OK) {
       Failed(FileErrorCode::kNotReadableErr,
              FailureType::kMojoPipeUnexpectedReadError);
       return;

third_party/blink/renderer/core/invisible_dom/invisible_dom.cc

@@ -46,9 +46,9 @@ bool InvisibleDOM::ActivateRangeIfNeeded(
   for (Node& node : range.Nodes()) {
     if (!InvisibleDOM::IsInsideInvisibleSubtree(node))
       continue;
-    for (Node& node : FlatTreeTraversal::AncestorsOf(node)) {
-      if (node.IsElementNode()) {
-        elements_to_activate.push_back(ToElement(node));
+    for (Node& ancestor_node : FlatTreeTraversal::AncestorsOf(node)) {
+      if (ancestor_node.IsElementNode()) {
+        elements_to_activate.push_back(ToElement(ancestor_node));
         break;
       }
     }

third_party/blink/renderer/core/loader/frame_loader.cc

@@ -893,8 +893,8 @@ void FrameLoader::StartNavigation(const FrameLoadRequest& passed_request,
                              ->ExperimentalFeaturesEnabled()) {
     initiator_csp = origin_document->GetContentSecurityPolicy()
                         ->ExposeForNavigationalChecks();
-    auto request = mojo::MakeRequest(&navigation_initiator);
-    origin_document->BindNavigationInitiatorRequest(std::move(request));
+    auto mojo_request = mojo::MakeRequest(&navigation_initiator);
+    origin_document->BindNavigationInitiatorRequest(std::move(mojo_request));
   }
 
   if (origin_document && origin_document->GetContentSecurityPolicy()) {

third_party/blink/renderer/core/script/modulator.cc

@@ -42,20 +42,22 @@ Modulator* Modulator::From(ScriptState* script_state) {
     // See comment in LocalDOMWindow::modulator_ for this workaround.
     LocalDOMWindow* window = document->ExecutingWindow();
     window->SetModulator(modulator);
-  } else if (auto* scope = DynamicTo<WorkletGlobalScope>(execution_context)) {
+  } else if (auto* worklet_scope =
+                 DynamicTo<WorkletGlobalScope>(execution_context)) {
     modulator = WorkletModulatorImpl::Create(script_state);
     Modulator::SetModulator(script_state, modulator);
 
     // See comment in WorkerOrWorkletGlobalScope::modulator_ for this
     // workaround.
-    scope->SetModulator(modulator);
-  } else if (auto* scope = DynamicTo<WorkerGlobalScope>(execution_context)) {
+    worklet_scope->SetModulator(modulator);
+  } else if (auto* worker_scope =
+                 DynamicTo<WorkerGlobalScope>(execution_context)) {
     modulator = WorkerModulatorImpl::Create(script_state);
     Modulator::SetModulator(script_state, modulator);
 
     // See comment in WorkerOrWorkletGlobalScope::modulator_ for this
     // workaround.
-    scope->SetModulator(modulator);
+    worker_scope->SetModulator(modulator);
   } else {
     NOTREACHED();
   }