[Fuchsia] Update AccessibilityBridgeTests so there are no loops

Remove the use of a do while loop in AccessibilityBridgeTests so tests
don't have the opportunity to run indefinitely.
Also remove special handling of the case where this is no root node as
this is now supported by the Semantics Manager.

Testing: CQ

Bug: 973095
Change-Id: I014506bf77fa11b7f33e115b601b9bfaa781b8e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1924714Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Commit-Queue: Sharon Yang <yangsharon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#717705}

fuchsia/engine/browser/accessibility_bridge.cc

@@ -82,13 +82,6 @@ void AccessibilityBridge::TryCommit() {
         std::move(to_delete_),
         base::BindRepeating(
             [](SemanticTree* tree, std::vector<uint32_t> nodes) {
-              for (auto i : nodes) {
-                if (i == 0u) {
-                  // TODO(fxb/41533): Remove this once SemanticsManager supports
-                  // deletion of entire tree.
-                  return;
-                }
-              }
               tree->DeleteSemanticNodes(std::move(nodes));
             },
             base::Unretained(tree_ptr_.get())));

fuchsia/engine/browser/accessibility_bridge_browsertest.cc

@@ -8,6 +8,7 @@
 #include <lib/ui/scenic/cpp/view_token_pair.h>
 #include <zircon/types.h>
 
+#include "base/auto_reset.h"
 #include "base/fuchsia/default_context.h"
 #include "base/fuchsia/scoped_service_binding.h"
 #include "base/fuchsia/service_directory_client.h"
@@ -15,7 +16,6 @@
 #include "base/test/bind_test_util.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "fuchsia/base/frame_test_util.h"
-#include "fuchsia/base/result_receiver.h"
 #include "fuchsia/base/test_navigation_listener.h"
 #include "fuchsia/engine/browser/accessibility_bridge.h"
 #include "fuchsia/engine/browser/frame_impl.h"
@@ -38,8 +38,8 @@ const char kPage2Title[] = "lots of nodes!";
 const char kButtonName[] = "a button";
 const char kNodeName[] = "last node";
 const char kParagraphName[] = "a third paragraph";
-const size_t kPage1NodeCount = 5;
-const size_t kPage2NodeCount = 200;
+const size_t kPage1NodeCount = 9;
+const size_t kPage2NodeCount = 190;
 
 class FakeSemanticTree
     : public fuchsia::accessibility::semantics::testing::SemanticTree_TestBase {
@@ -65,7 +65,7 @@ class FakeSemanticTree
   void CommitUpdates(CommitUpdatesCallback callback) final {
     callback();
     if (on_commit_updates_)
-      std::move(on_commit_updates_).Run();
+      on_commit_updates_.Run();
   }
 
   void NotImplemented_(const std::string& name) final {
@@ -74,16 +74,18 @@ class FakeSemanticTree
 
   void RunUntilNodeCountAtLeast(size_t count) {
     DCHECK(!on_commit_updates_);
-
     if (nodes_.size() >= count)
       return;
 
-    // May take multiple commits before node count is sufficient.
-    do {
-      base::RunLoop run_loop;
-      on_commit_updates_ = run_loop.QuitClosure();
-      run_loop.Run();
-    } while (nodes_.size() < count);
+    base::RunLoop run_loop;
+    base::AutoReset<base::RepeatingClosure> auto_reset(
+        &on_commit_updates_,
+        base::BindLambdaForTesting([this, count, &run_loop]() {
+          if (nodes_.size() >= count) {
+            run_loop.Quit();
+          }
+        }));
+    run_loop.Run();
   }
 
   bool HasNodeWithLabel(base::StringPiece name) {
@@ -98,7 +100,7 @@ class FakeSemanticTree
 
  private:
   std::vector<Node> nodes_;
-  base::OnceClosure on_commit_updates_;
+  base::RepeatingClosure on_commit_updates_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeSemanticTree);
 };