Reimplement automation API on top of C++-backed AXTree.

chrome/renderer/extensions/automation_internal_custom_bindings.h

 // Copyright 2014 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 CHROME_RENDERER_EXTENSIONS_AUTOMATION_INTERNAL_CUSTOM_BINDINGS_H_
 #define CHROME_RENDERER_EXTENSIONS_AUTOMATION_INTERNAL_CUSTOM_BINDINGS_H_
 
 #include "base/compiler_specific.h"
+#include "chrome/common/extensions/api/automation.h"
 #include "extensions/renderer/object_backed_native_handler.h"
 #include "ipc/ipc_message.h"
 #include "ui/accessibility/ax_tree.h"
 #include "v8/include/v8.h"
 
 struct ExtensionMsg_AccessibilityEventParams;
 
 namespace extensions {
 
 class AutomationMessageFilter;
 
+struct TreeCache {
+  TreeCache();
+  ~TreeCache();
+
+  int tab_id;
+  int tree_id;
+
+  gfx::Vector2d location_offset;
+  ui::AXTree tree;
+};
+
 // The native component of custom bindings for the chrome.automationInternal
 // API.
-class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
+class AutomationInternalCustomBindings : public ObjectBackedNativeHandler,
+                                         public ui::AXTreeDelegate {
  public:
   explicit AutomationInternalCustomBindings(ScriptContext* context);
 
   ~AutomationInternalCustomBindings() override;
 
-  bool OnMessageReceived(const IPC::Message& message);
+  void OnMessageReceived(const IPC::Message& message);
 
  private:
   // Returns whether this extension has the "interact" permission set (either
   // explicitly or implicitly after manifest parsing).
   void IsInteractPermitted(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   // Returns an object with bindings that will be added to the
   // chrome.automation namespace.
   void GetSchemaAdditions(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   // Get the routing ID for the extension.
   void GetRoutingID(const v8::FunctionCallbackInfo<v8::Value>& args);
 
+  // This is called by automation_internal_custom_bindings.js to indicate
+  // that an API was called that needs access to accessibility trees. This
+  // enables the MessageFilter that allows us to listen to accessibility
+  // events forwarded to this process.
+  void StartCachingAccessibilityTrees(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Called when an accessibility tree is destroyed and needs to be
+  // removed from our cache.
+  // Args: int ax_tree_id
+  void DestroyAccessibilityTree(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  //
+  // Access the cached accessibility trees and properties of their nodes.
+  //
+
+  // Args: int ax_tree_id, Returns: int root_node_id.
+  void GetRootID(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, Returns: int parent_node_id.
+  void GetParentID(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, Returns: int child_count.
+  void GetChildCount(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, Returns: int child_id.
+  void GetChildIDAtIndex(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, Returns: int index_in_parent.
+  void GetIndexInParent(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id
+  // Returns: JS object with a string key for each state flag that's set.
+  void GetState(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, Returns: string role_name
+  void GetRole(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id
+  // Returns: JS object with {left, top, width, height}
+  void GetLocation(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, string attribute_name
+  // Returns: string attribute_value.
+  void GetStringAttribute(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, string attribute_name
+  // Returns: bool attribute_value.
+  void GetBoolAttribute(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, string attribute_name
+  // Returns: int attribute_value.
+  void GetIntAttribute(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, string attribute_name
+  // Returns: float attribute_value.
+  void GetFloatAttribute(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, string attribute_name
+  // Returns: JS array of int attribute_values.
+  void GetIntListAttribute(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Args: int ax_tree_id, int node_id, string attribute_name
+  // Returns: string attribute_value.
+  void GetHtmlAttribute(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  //
+  // Helper functions.
+  //
+
+  // Throw an exception if we get bad arguments.
+  void ThrowInvalidArgumentsException(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // For any function that takes int ax_tree_id, int node_id as its first
+  // two arguments, returns the tree and node it corresponds to, or returns
+  // false if not found.
+  bool GetNodeHelper(
+      const v8::FunctionCallbackInfo<v8::Value>& args,
+      TreeCache** out_cache,
+      ui::AXNode** out_node);
+
+  // For any function that takes int ax_tree_id, int node_id, string attr
+  // as its first, returns the node it corresponds to and the string as
+  // a UTF8 string.
+  bool GetAttributeHelper(
+      const v8::FunctionCallbackInfo<v8::Value>& args,
+      ui::AXNode** out_node,
+      std::string* out_attribute_name);
+
+  // Create a V8 string from a string.
+  v8::Local<v8::Value> CreateV8String(const char* str);
+  v8::Local<v8::Value> CreateV8String(const std::string& str);
+
   // Handle accessibility events from the browser process.
   void OnAccessibilityEvent(
       const ExtensionMsg_AccessibilityEventParams& params);
 
+  // AXTreeDelegate implementation.
+  void OnNodeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override;
+  void OnSubtreeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override;
+  void OnNodeCreated(ui::AXTree* tree, ui::AXNode* node) override;
+  void OnNodeChanged(ui::AXTree* tree, ui::AXNode* node) override;
+  void OnAtomicUpdateFinished(ui::AXTree* tree,
+                              bool root_changed,
+                              const std::vector<Change>& changes) override;
+
+  void SendTreeChangeEvent(api::automation::TreeChangeType change_type,
+                           ui::AXTree* tree,
+                           ui::AXNode* node);
+
+  base::hash_map<int, TreeCache*> tree_id_to_tree_cache_map_;
+  base::hash_map<ui::AXTree*, TreeCache*> axtree_to_tree_cache_map_;
   scoped_refptr<AutomationMessageFilter> message_filter_;
 
   DISALLOW_COPY_AND_ASSIGN(AutomationInternalCustomBindings);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_RENDERER_EXTENSIONS_AUTOMATION_INTERNAL_CUSTOM_BINDINGS_H_