Cross-process iframe accessibility.

content/browser/accessibility/browser_accessibility_manager.h

 // 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.
 
 #ifndef CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_
 
 #include <vector>
 
 #include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/web/WebAXEnums.h"
 #include "ui/accessibility/ax_node_data.h"
-#include "ui/accessibility/ax_tree.h"
+#include "ui/accessibility/ax_serializable_tree.h"
 #include "ui/accessibility/ax_tree_update.h"
 #include "ui/gfx/native_widget_types.h"
 
 struct AccessibilityHostMsg_EventParams;
 struct AccessibilityHostMsg_LocationChangeParams;
 
 namespace content {
 class BrowserAccessibility;
+class BrowserAccessibilityManager;
 #if defined(OS_ANDROID)
 class BrowserAccessibilityManagerAndroid;
 #endif
 #if defined(OS_WIN)
 class BrowserAccessibilityManagerWin;
 #endif
 
+const int kNoFrameId = -1;

[Charlie Reis, 2014/08/21 19:23:27]

This is a bit ambiguous for a content-wide constant.  Beyond clarifying frame
routing ID vs FrameTreeNode ID vs node ID, we should probably add "Ax" in the
name.

[dmazzoni, 2014/08/25 06:49:36]

WIth the other changes, this is only needed in browser_accessibility.cc now.
Frame tree node ids start at 1, so maybe we don't need a constant at all? I can
just document that it's only valid if nonzero.

+
 // For testing.
 CONTENT_EXPORT ui::AXTreeUpdate MakeAXTreeUpdate(
     const ui::AXNodeData& node,
     const ui::AXNodeData& node2 = ui::AXNodeData(),
     const ui::AXNodeData& node3 = ui::AXNodeData(),
     const ui::AXNodeData& node4 = ui::AXNodeData(),
     const ui::AXNodeData& node5 = ui::AXNodeData(),
     const ui::AXNodeData& node6 = ui::AXNodeData(),
     const ui::AXNodeData& node7 = ui::AXNodeData(),
     const ui::AXNodeData& node8 = ui::AXNodeData(),
@@ skipping 14 matching lines @@
       int acc_obj_id, int start_offset, int end_offset) = 0;
   virtual bool AccessibilityViewHasFocus() const = 0;
   virtual gfx::Rect AccessibilityGetViewBounds() const = 0;
   virtual gfx::Point AccessibilityOriginInScreen(
       const gfx::Rect& bounds) const = 0;
   virtual void AccessibilityHitTest(
       const gfx::Point& point) = 0;
   virtual void AccessibilityFatalError() = 0;
   virtual gfx::AcceleratedWidget AccessibilityGetAcceleratedWidget() = 0;
   virtual gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() = 0;
+  virtual BrowserAccessibilityManager* AccessibilityGetChildFrame(
+      int64 frame_id) = 0;
+  virtual BrowserAccessibilityManager* AccessibilityGetParentFrame() = 0;
 };
 
 class CONTENT_EXPORT BrowserAccessibilityFactory {
  public:
   virtual ~BrowserAccessibilityFactory() {}
 
   // Create an instance of BrowserAccessibility and return a new
   // reference to it.
   virtual BrowserAccessibility* Create();
 };
@@ skipping 106 matching lines @@
   virtual void OnNodeChanged(ui::AXNode* node) OVERRIDE;
   virtual void OnNodeCreationFinished(ui::AXNode* node) OVERRIDE;
   virtual void OnNodeChangeFinished(ui::AXNode* node) OVERRIDE;
   virtual void OnRootChanged(ui::AXNode* new_root) OVERRIDE {}
 
   BrowserAccessibilityDelegate* delegate() const { return delegate_; }
   void set_delegate(BrowserAccessibilityDelegate* delegate) {
     delegate_ = delegate;
   }
 
+  // Get a snapshot of the current tree as an AXTreeUpdate.
+  ui::AXTreeUpdate SnapshotAXTreeForTesting();
+
+  // Frame tree support.
+  void SetNodeIdInParentFrame(int32 node_id);
+  void SetChildFrameId(int32 node_id, int64 child_frame_id);
+  BrowserAccessibility* GetCrossFrameParent();
+
  protected:
   BrowserAccessibilityManager(
       BrowserAccessibilityDelegate* delegate,
       BrowserAccessibilityFactory* factory);
 
   BrowserAccessibilityManager(
       const ui::AXTreeUpdate& initial_tree,
       BrowserAccessibilityDelegate* delegate,
       BrowserAccessibilityFactory* factory);
 
@@ skipping 16 matching lines @@
     // touch event was within the bounds of the currently focused object.
     // Otherwise we'll just wait to see if focus changes.
     OSK_ALLOWED_WITHIN_FOCUSED_OBJECT,
 
     // Focus has changed within a tab that's already visible. Allow the
     // on-screen keyboard to show anytime that a touch event leads to an
     // editable text control getting focus.
     OSK_ALLOWED
   };
 
-  // Update a set of nodes using data received from the renderer
-  // process.
-  bool UpdateNodes(const std::vector<ui::AXNodeData>& nodes);
-
-  // Update one node from the tree using data received from the renderer
-  // process. Returns true on success, false on fatal error.
-  bool UpdateNode(const ui::AXNodeData& src);
-
-  void SetRoot(BrowserAccessibility* root);
-
-  BrowserAccessibility* CreateNode(
-      BrowserAccessibility* parent,
-      int32 id,
-      int32 index_in_parent);
-
  protected:
   // The object that can perform actions on our behalf.
   BrowserAccessibilityDelegate* delegate_;
 
   // Factory to create BrowserAccessibility objects (for dependency injection).
   scoped_ptr<BrowserAccessibilityFactory> factory_;
 
   // The underlying tree of accessibility objects.
-  scoped_ptr<ui::AXTree> tree_;
+  scoped_ptr<ui::AXSerializableTree> tree_;
 
   // The node that currently has focus.
   ui::AXNode* focus_;
 
   // A mapping from a node id to its wrapper of type BrowserAccessibility.
   base::hash_map<int32, BrowserAccessibility*> id_wrapper_map_;
 
+  // This is set if this tree's frame is the child of another frame.
+  // It's the id of the node in the parent frame that's the parent of this
+  // frame's root object.

[Charlie Reis, 2014/08/20 20:37:13]

This comment is kind of hard to follow.  Maybe it would be clearer with an
example?

[dmazzoni, 2014/08/20 20:57:17]

Sure.

I'll work on the comment, but for purposes of your understanding the code
review:

Imagine frame P has an iframe element with node id 37, where that id is relative
to its frame.

The iframe's accessibility tree is this BrowserAccessibilityManager. This field
tells us the id - 37 - of the element that hosts this whole frame in the parent
frame.

This is needed so we can walk back up the tree. If the client requests the
parent of the root of this tree, we need to return the object id=37 from the
parent frame.

[dmazzoni, 2014/08/25 06:49:36]

This is gone now.

+  uint32 node_id_in_parent_frame_;
+
   // The on-screen keyboard state.
   OnScreenKeyboardState osk_state_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_