Update WebContents::RequestAXTreeSnapshot() to OnceCallback.

BUG=714018

Change-Id: Ic6fa05a2ebd6ca21bd1b2a349a58f7a419a3465d
Reviewed-on: https://chromium-review.googlesource.com/952991Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Luis Hector Chavez <lhchavez@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541881}

chrome/browser/chromeos/arc/voice_interaction/arc_voice_interaction_arc_home_service.cc

@@ -318,9 +318,8 @@ void ArcVoiceInteractionArcHomeService::GetVoiceInteractionStructure(
                        ->GetHost()
                        ->GetRootTransform();
   float scale_factor = ash::GetScaleFactorForTransform(transform);
-  web_contents->RequestAXTreeSnapshot(base::Bind(
-      &RequestVoiceInteractionStructureCallback,
-      base::Passed(std::move(callback)),
+  web_contents->RequestAXTreeSnapshot(base::BindOnce(
+      &RequestVoiceInteractionStructureCallback, std::move(callback),
       gfx::ConvertRectToPixel(scale_factor, browser->window()->GetBounds()),
       web_contents->GetLastCommittedURL().spec(), web_contents->GetTitle()));
 }

chrome/browser/chromeos/arc/voice_interaction/arc_voice_interaction_arc_home_service_browsertest.cc

@@ -58,7 +58,7 @@ class ArcVoiceInteractionArcHomeServiceTest : public InProcessBrowserTest {
     ui_test_utils::NavigateToURL(browser(), url);
     auto* web_contents = browser()->tab_strip_model()->GetActiveWebContents();
     AXTreeSnapshotWaiter waiter;
-    web_contents->RequestAXTreeSnapshot(base::Bind(
+    web_contents->RequestAXTreeSnapshot(base::BindOnce(
         &AXTreeSnapshotWaiter::ReceiveSnapshot, base::Unretained(&waiter)));
     waiter.Wait();
     auto node = ui::AXSnapshotNodeAndroid::Create(waiter.snapshot(), false);

content/browser/accessibility/snapshot_ax_tree_browsertest.cc

@@ -74,9 +74,8 @@ IN_PROC_BROWSER_TEST_F(SnapshotAXTreeBrowserTest,
       static_cast<WebContentsImpl*>(shell()->web_contents());
 
   AXTreeSnapshotWaiter waiter;
-  web_contents->RequestAXTreeSnapshot(
-      base::Bind(&AXTreeSnapshotWaiter::ReceiveSnapshot,
-                 base::Unretained(&waiter)));
+  web_contents->RequestAXTreeSnapshot(base::BindOnce(
+      &AXTreeSnapshotWaiter::ReceiveSnapshot, base::Unretained(&waiter)));
   waiter.Wait();
 
   // Dump the whole tree if one of the assertions below fails
@@ -109,9 +108,8 @@ IN_PROC_BROWSER_TEST_F(SnapshotAXTreeBrowserTest,
       "/accessibility/snapshot/inner.html"));
 
   AXTreeSnapshotWaiter waiter;
-  web_contents->RequestAXTreeSnapshot(
-      base::Bind(&AXTreeSnapshotWaiter::ReceiveSnapshot,
-                 base::Unretained(&waiter)));
+  web_contents->RequestAXTreeSnapshot(base::BindOnce(
+      &AXTreeSnapshotWaiter::ReceiveSnapshot, base::Unretained(&waiter)));
   waiter.Wait();
 
   // Dump the whole tree if one of the assertions below fails

content/browser/frame_host/render_frame_host_impl.cc

@@ -1892,8 +1892,8 @@ void RenderFrameHostImpl::OnRenderProcessGone(int status, int exit_code) {
 
   // Execute any pending AX tree snapshot callbacks with an empty response,
   // since we're never going to get a response from this renderer.
-  for (const auto& iter : ax_tree_snapshot_callbacks_)
-    iter.second.Run(ui::AXTreeUpdate());
+  for (auto& iter : ax_tree_snapshot_callbacks_)
+    std::move(iter.second).Run(ui::AXTreeUpdate());
 
 #if defined(OS_ANDROID)
   // Execute any pending Samsung smart clip callbacks.
@@ -2629,7 +2629,7 @@ void RenderFrameHostImpl::OnAccessibilitySnapshotResponse(
       AXContentTreeDataToAXTreeData(&dst_snapshot.tree_data);
       dst_snapshot.has_tree_data = true;
     }
-    it->second.Run(dst_snapshot);
+    std::move(it->second).Run(dst_snapshot);
     ax_tree_snapshot_callbacks_.erase(it);
   } else {
     NOTREACHED() << "Received AX tree snapshot response for unknown id";
@@ -3952,7 +3952,8 @@ void RenderFrameHostImpl::RequestAXTreeSnapshot(
   static int next_id = 1;
   int callback_id = next_id++;
   Send(new AccessibilityMsg_SnapshotTree(routing_id_, callback_id));
-  ax_tree_snapshot_callbacks_.insert(std::make_pair(callback_id, callback));
+  ax_tree_snapshot_callbacks_.insert(
+      std::make_pair(callback_id, std::move(callback)));
 }
 
 void RenderFrameHostImpl::SetAccessibilityCallbackForTesting(

content/browser/frame_host/render_frame_host_impl.h

@@ -158,8 +158,7 @@ class CONTENT_EXPORT RenderFrameHostImpl
       public CSPContext {
  public:
   using AXTreeSnapshotCallback =
-      base::Callback<void(
-          const ui::AXTreeUpdate&)>;
+      base::OnceCallback<void(const ui::AXTreeUpdate&)>;
 
   // An accessibility reset is only allowed to prevent very rare corner cases
   // or race conditions where the browser and renderer get out of sync. If

content/browser/web_contents/web_contents_android.cc

@@ -561,10 +561,9 @@ void WebContentsAndroid::RequestAccessibilitySnapshot(
   ScopedJavaGlobalRef<jobject> j_callback;
   j_callback.Reset(env, callback);
 
-  WebContentsImpl::AXTreeSnapshotCallback snapshot_callback =
-      base::Bind(&AXTreeSnapshotCallback, j_callback);
-  static_cast<WebContentsImpl*>(web_contents_)->RequestAXTreeSnapshot(
-      snapshot_callback);
+  static_cast<WebContentsImpl*>(web_contents_)
+      ->RequestAXTreeSnapshot(
+          base::BindOnce(&AXTreeSnapshotCallback, j_callback));
 }
 
 ScopedJavaLocalRef<jstring> WebContentsAndroid::GetEncoding(

content/browser/web_contents/web_contents_impl.cc

@@ -219,8 +219,7 @@ void ResetAccessibility(RenderFrameHost* rfh) {
   static_cast<RenderFrameHostImpl*>(rfh)->AccessibilityReset();
 }
 
-using AXTreeSnapshotCallback =
-      base::Callback<void(const ui::AXTreeUpdate&)>;
+using AXTreeSnapshotCallback = WebContents::AXTreeSnapshotCallback;
 
 // Helper class used by WebContentsImpl::RequestAXTreeSnapshot.
 // Handles the callbacks from parallel snapshot requests to each frame,
@@ -229,14 +228,12 @@ using AXTreeSnapshotCallback =
 class AXTreeSnapshotCombiner : public base::RefCounted<AXTreeSnapshotCombiner> {
  public:
   explicit AXTreeSnapshotCombiner(AXTreeSnapshotCallback callback)
-      : callback_(callback) {
-  }
+      : callback_(std::move(callback)) {}
 
   AXTreeSnapshotCallback AddFrame(bool is_root) {
     // Adds a reference to |this|.
-    return base::Bind(&AXTreeSnapshotCombiner::ReceiveSnapshot,
-                      this,
-                      is_root);
+    return base::BindOnce(&AXTreeSnapshotCombiner::ReceiveSnapshot, this,
+                          is_root);
   }
 
   void ReceiveSnapshot(bool is_root, const ui::AXTreeUpdate& snapshot) {
@@ -250,7 +247,7 @@ class AXTreeSnapshotCombiner : public base::RefCounted<AXTreeSnapshotCombiner> {
   // when there are no more references to this object.
   ~AXTreeSnapshotCombiner() {
     combiner_.Combine();
-    callback_.Run(combiner_.combined());
+    std::move(callback_).Run(combiner_.combined());
   }
 
   ui::AXTreeCombiner combiner_;
@@ -1072,13 +1069,13 @@ void WebContentsImpl::AddAccessibilityMode(ui::AXMode mode) {
   SetAccessibilityMode(new_mode);
 }
 
-void WebContentsImpl::RequestAXTreeSnapshot(
-    const AXTreeSnapshotCallback& callback) {
+void WebContentsImpl::RequestAXTreeSnapshot(AXTreeSnapshotCallback callback) {
   // Send a request to each of the frames in parallel. Each one will return
   // an accessibility tree snapshot, and AXTreeSnapshotCombiner will combine
   // them into a single tree and call |callback| with that result, then
   // delete |combiner|.
-  AXTreeSnapshotCombiner* combiner = new AXTreeSnapshotCombiner(callback);
+  AXTreeSnapshotCombiner* combiner =
+      new AXTreeSnapshotCombiner(std::move(callback));
   for (FrameTreeNode* frame_tree_node : frame_tree_.Nodes()) {
     bool is_root = frame_tree_node->parent() == nullptr;
     frame_tree_node->current_frame_host()->RequestAXTreeSnapshot(

content/browser/web_contents/web_contents_impl.h

@@ -341,7 +341,7 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
   bool IsWaitingForResponse() const override;
   const net::LoadStateWithParam& GetLoadState() const override;
   const base::string16& GetLoadStateHost() const override;
-  void RequestAXTreeSnapshot(const AXTreeSnapshotCallback& callback) override;
+  void RequestAXTreeSnapshot(AXTreeSnapshotCallback callback) override;
   uint64_t GetUploadSize() const override;
   uint64_t GetUploadPosition() const override;
   const std::string& GetEncoding() const override;

content/public/browser/web_contents.h

@@ -300,9 +300,9 @@ class WebContents : public PageNavigator,
 
   // Request a one-time snapshot of the accessibility tree without changing
   // the accessibility mode.
-  using AXTreeSnapshotCallback = base::Callback<void(const ui::AXTreeUpdate&)>;
-  virtual void RequestAXTreeSnapshot(
-      const AXTreeSnapshotCallback& callback) = 0;
+  using AXTreeSnapshotCallback =
+      base::OnceCallback<void(const ui::AXTreeUpdate&)>;
+  virtual void RequestAXTreeSnapshot(AXTreeSnapshotCallback callback) = 0;
 
   // Causes the current page to be closed, including running its onunload event
   // handler.