Forward accessibility events to the automation extension process.

chrome/renderer/extensions/automation_internal_custom_bindings.cc

 // 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.
 
 #include "chrome/renderer/extensions/automation_internal_custom_bindings.h"
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
+#include "chrome/common/extensions/chrome_extension_messages.h"
 #include "chrome/common/extensions/manifest_handlers/automation.h"
 #include "content/public/child/v8_value_converter.h"
+#include "content/public/renderer/render_thread.h"
+#include "content/public/renderer/render_view.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/manifest.h"
 #include "extensions/renderer/script_context.h"
+#include "ipc/message_filter.h"
 #include "ui/accessibility/ax_enums.h"
+#include "ui/accessibility/ax_node.h"
 
 namespace {
 
 // Helper to convert an enum to a V8 object.
 template <typename EnumType>
 v8::Local<v8::Object> ToEnumObject(v8::Isolate* isolate,
                                    EnumType start_after,
                                    EnumType end_at) {
   v8::Local<v8::Object> object = v8::Object::New(isolate);
   for (int i = start_after + 1; i <= end_at; ++i) {
     v8::Local<v8::String> value = v8::String::NewFromUtf8(
         isolate, ui::ToString(static_cast<EnumType>(i)).c_str());
     object->Set(value, value);
   }
   return object;
 }
 
 }  // namespace
 
 namespace extensions {
 
+class AutomationMessageFilter : public IPC::MessageFilter {
+ public:
+  explicit AutomationMessageFilter(AutomationInternalCustomBindings* owner)
+      : owner_(owner) {

[dcheng, 2015/06/06 00:00:52]

Is it valid to call this constructor with no owner? It doesn't look like we ever
do, so maybe DCHECK(owner)?

[dmazzoni, 2015/06/08 18:02:58]

Done.

+    content::RenderThread::Get()->AddFilter(this);
+  }
+
+  void Detach() {

[dcheng, 2015/06/06 00:00:52]

Who calls Detach()?

[dmazzoni, 2015/06/08 18:02:58]

Oops, meant to call this in ~AutomationInternalCustomBindings(). Good catch.

+    owner_ = nullptr;
+  }
+
+  // IPC::MessageFilter
+  bool OnMessageReceived(const IPC::Message& message) override {
+    if (owner_)
+      return owner_->OnMessageReceived(message);
+    else
+      return false;
+  }
+
+private:
+  ~AutomationMessageFilter() override {
+    content::RenderThread* render_thread = content::RenderThread::Get();

[dcheng, 2015/06/06 00:00:52]

Why would this be null? To me, this conditional makes it seem like we're not
sure when this object dies in relation to the RenderThread?

[dmazzoni, 2015/06/08 18:02:57]

Looks like it shouldn't be null, removed the check.

+    if (render_thread)
+      render_thread->RemoveFilter(this);
+  }
+
+  AutomationInternalCustomBindings* owner_;

[dcheng, 2015/06/06 00:00:52]

Since we don't use Detach() anymore, make this an
AutomationInternalCustomBindings* const owner_?

[dmazzoni, 2015/06/08 18:02:58]

I think we need Detach() because the message filter is refcounted and can
outlive the owner.

+
+  DISALLOW_COPY_AND_ASSIGN(AutomationMessageFilter);
+};
+
 AutomationInternalCustomBindings::AutomationInternalCustomBindings(
     ScriptContext* context) : ObjectBackedNativeHandler(context) {
   RouteFunction(
       "IsInteractPermitted",
       base::Bind(&AutomationInternalCustomBindings::IsInteractPermitted,
                  base::Unretained(this)));
   RouteFunction(
       "GetSchemaAdditions",
       base::Bind(&AutomationInternalCustomBindings::GetSchemaAdditions,
                  base::Unretained(this)));
+  RouteFunction(
+      "GetRoutingID",
+      base::Bind(&AutomationInternalCustomBindings::GetRoutingID,
+                 base::Unretained(this)));

[dcheng, 2015/06/06 00:00:52]

In general, it's nice to document why base::Unretained() is safe.

[dmazzoni, 2015/06/08 18:02:58]

Done.

+
+  message_filter_ = new AutomationMessageFilter(this);
 }
 
 AutomationInternalCustomBindings::~AutomationInternalCustomBindings() {
 }
 
+bool AutomationInternalCustomBindings::OnMessageReceived(
+    const IPC::Message& message) {
+  IPC_BEGIN_MESSAGE_MAP(AutomationInternalCustomBindings, message)
+    IPC_MESSAGE_HANDLER(ExtensionMsg_AccessibilityEvent, OnAccessibilityEvent)
+  IPC_END_MESSAGE_MAP()
+
+  // Always return false in case there are multiple
+  // AutomationInternalCustomBindings instances attached to the same thread.
+  return false;
+}
+
 void AutomationInternalCustomBindings::IsInteractPermitted(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   const Extension* extension = context()->extension();
   CHECK(extension);
   const AutomationInfo* automation_info = AutomationInfo::Get(extension);
   CHECK(automation_info);
   args.GetReturnValue().Set(
       v8::Boolean::New(GetIsolate(), automation_info->interact));
 }
 
+void AutomationInternalCustomBindings::GetRoutingID(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  int routing_id = context()->GetRenderView()->GetRoutingID();
+  args.GetReturnValue().Set(v8::Integer::New(GetIsolate(), routing_id));
+}
+
 void AutomationInternalCustomBindings::GetSchemaAdditions(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Local<v8::Object> additions = v8::Object::New(GetIsolate());
 
   additions->Set(
       v8::String::NewFromUtf8(GetIsolate(), "EventType"),
       ToEnumObject(GetIsolate(), ui::AX_EVENT_NONE, ui::AX_EVENT_LAST));
 
   additions->Set(
       v8::String::NewFromUtf8(GetIsolate(), "RoleType"),
       ToEnumObject(GetIsolate(), ui::AX_ROLE_NONE, ui::AX_ROLE_LAST));
 
   additions->Set(
       v8::String::NewFromUtf8(GetIsolate(), "StateType"),
       ToEnumObject(GetIsolate(), ui::AX_STATE_NONE, ui::AX_STATE_LAST));
 
   additions->Set(
       v8::String::NewFromUtf8(GetIsolate(), "TreeChangeType"),
       ToEnumObject(GetIsolate(), ui::AX_MUTATION_NONE, ui::AX_MUTATION_LAST));
 
   args.GetReturnValue().Set(additions);
 }
 
+void AutomationInternalCustomBindings::OnAccessibilityEvent(
+    const ExtensionMsg_AccessibilityEventParams& params) {
+  // TODO(dmazzoni): finish implementing this.

[dcheng, 2015/06/06 00:00:52]

Please add me as a reviewer on the change where you finish implementing this.

[dmazzoni, 2015/06/08 18:02:57]

Done: https://codereview.chromium.org/1155183006/

It's basically done and working now, I'm just trying to clean it up and get it
reviewed in pieces.

+}
+
 }  // namespace extensions