Hook up guest browser plugins to the accessibility tree.

content/browser/frame_host/frame_accessibility.cc

Index: content/browser/frame_host/frame_accessibility.cc
diff --git a/content/browser/frame_host/frame_accessibility.cc b/content/browser/frame_host/frame_accessibility.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3b99a0512decad7382608fe9ab143838ed272d0b
--- /dev/null
+++ b/content/browser/frame_host/frame_accessibility.cc
@@ -0,0 +1,174 @@
+// 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 "content/browser/frame_host/frame_accessibility.h"
+
+#include "content/browser/frame_host/frame_tree.h"
+#include "content/browser/frame_host/frame_tree_node.h"
+#include "content/browser/frame_host/render_frame_host_delegate.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_plugin_guest_manager.h"
+#include "content/public/browser/web_contents.h"

[dmazzoni, 2014/09/12 07:34:34]

Currently this inclusion is not allowed.

Should I add some code that queries BrowserPluginGuestManager to the delegate
interface, or can you think of a simpler way?

[Fady Samuel, 2014/09/12 16:05:11]

I can look into changing GetGuestByInstanceID to take in a RFH and return a RFH.
I'll get back to you on that in a couple of hours.

+
+namespace content {
+
+// static
+FrameAccessibility* FrameAccessibility::GetInstance() {
+  return Singleton<FrameAccessibility>::get();
+}
+
+FrameAccessibility::ChildFrameMapping::ChildFrameMapping()
+    : parent_frame_host(NULL),
+      accessibility_node_id(0),
+      child_frame_tree_node_id(0),
+      browser_plugin_instance_id(0) {}
+
+FrameAccessibility::FrameAccessibility() {}
+
+FrameAccessibility::~FrameAccessibility() {}
+
+void FrameAccessibility::AddChildFrame(
+    RenderFrameHostImpl* parent_frame_host,
+    int accessibility_node_id,
+    int64 child_frame_tree_node_id) {
+  for (std::vector<ChildFrameMapping>::iterator iter = mappings_.begin();
+       iter != mappings_.end();
+       ++iter) {
+    if (iter->parent_frame_host == parent_frame_host &&
+        (iter->accessibility_node_id == accessibility_node_id ||
+         iter->child_frame_tree_node_id == child_frame_tree_node_id)) {
+      iter->accessibility_node_id = accessibility_node_id;

[Charlie Reis, 2014/09/11 21:46:21]

What cases require us to update an existing record?  It'd be nice to prevent
silently corrupting the map if that case isn't expected.

[dmazzoni, 2014/09/12 07:34:34]

There are several cases where both could change: if an iframe navigates,
child_frame_tree_node_id could change, and if the iframe element in the
accessibility tree gets recreated (like if it's hidden and then shown), then
accessibility_node_id could change.

The better fix is for the renderer to keep track of this and clear an invalid
mapping first before adding the new one. I added a TODO for that and filed bug
413464.

[Charlie Reis, 2014/09/12 21:01:58]

The frame routing ID might change during navigation, but the FrameTreeNode ID
shouldn't ever change unless the whole frame were removed from the page.
Yep, that makes sense.
Sounds good.

+      iter->child_frame_tree_node_id = child_frame_tree_node_id;
+      return;
+    }
+  }
+
+  ChildFrameMapping new_mapping;
+  new_mapping.parent_frame_host = parent_frame_host;
+  new_mapping.accessibility_node_id = accessibility_node_id;
+  new_mapping.child_frame_tree_node_id = child_frame_tree_node_id;
+  mappings_.push_back(new_mapping);
+}
+
+void FrameAccessibility::AddGuestWebContents(
+    RenderFrameHostImpl* parent_frame_host,
+    int accessibility_node_id,
+    int browser_plugin_instance_id) {
+  for (std::vector<ChildFrameMapping>::iterator iter = mappings_.begin();
+       iter != mappings_.end();
+       ++iter) {
+    if (iter->parent_frame_host == parent_frame_host &&
+        (iter->accessibility_node_id == accessibility_node_id ||
+         iter->browser_plugin_instance_id == browser_plugin_instance_id)) {
+      iter->accessibility_node_id = accessibility_node_id;
+      iter->browser_plugin_instance_id = browser_plugin_instance_id;
+      return;
+    }
+  }
+
+  ChildFrameMapping new_mapping;
+  new_mapping.parent_frame_host = parent_frame_host;
+  new_mapping.accessibility_node_id = accessibility_node_id;
+  new_mapping.browser_plugin_instance_id = browser_plugin_instance_id;
+  mappings_.push_back(new_mapping);
+}
+
+void FrameAccessibility::OnRenderFrameHostDestroyed(
+    RenderFrameHostImpl* render_frame_host) {
+  // Since the order doesn't matter, the fastest way to remove all items
+  // with this render_frame_host is to iterate over the vector backwards,
+  // swapping each one with the back element if we need to delete it.
+  int initial_len = static_cast<int>(mappings_.size());
+  for (int i = initial_len - 1; i >= 0; i--) {
+    if (mappings_[i].parent_frame_host == render_frame_host) {
+      mappings_[i] = mappings_.back();
+      mappings_.pop_back();
+    }
+  }
+}
+
+RenderFrameHostImpl* FrameAccessibility::GetChild(
+    RenderFrameHostImpl* parent_frame_host,
+    int accessibility_node_id) {
+  for (std::vector<ChildFrameMapping>::iterator iter = mappings_.begin();
+       iter != mappings_.end();
+       ++iter) {
+    if (iter->parent_frame_host != parent_frame_host ||
+        iter->accessibility_node_id != accessibility_node_id) {
+      continue;
+    }
+
+    if (iter->child_frame_tree_node_id) {
+      FrameTreeNode* child_node =
+          FrameTree::GloballyFindByID(iter->child_frame_tree_node_id);
+      if (!child_node)
+        return NULL;
+
+      // We should have gotten a node in the same frame tree.
+      CHECK_EQ(child_node->frame_tree(),
+               parent_frame_host->frame_tree_node()->frame_tree());
+
+      return child_node->current_frame_host();
+    }
+
+    if (iter->browser_plugin_instance_id) {
+      WebContents* web_contents =
+          parent_frame_host->delegate()->GetAsWebContents();
+      if (!web_contents)
+        continue;
+      BrowserPluginGuestManager* guest_manager =
+          web_contents->GetBrowserContext()->GetGuestManager();
+      WebContents* guest = guest_manager->GetGuestByInstanceID(
+          web_contents, iter->browser_plugin_instance_id);
+      return static_cast<RenderFrameHostImpl*>(guest->GetMainFrame());
+    }
+  }
+
+  return NULL;
+}
+
+bool FrameAccessibility::GetParent(
+    RenderFrameHostImpl* child_frame_host,
+    RenderFrameHostImpl** out_parent_frame_host,
+    int* out_accessibility_node_id) {
+  for (std::vector<ChildFrameMapping>::iterator iter = mappings_.begin();
+       iter != mappings_.end();
+       ++iter) {
+    if (iter->child_frame_tree_node_id) {
+      FrameTreeNode* child_node =
+          FrameTree::GloballyFindByID(iter->child_frame_tree_node_id);
+      if (child_node &&
+          child_node->current_frame_host() == child_frame_host) {
+        if (out_parent_frame_host)
+          *out_parent_frame_host = iter->parent_frame_host;
+        if (out_accessibility_node_id)
+          *out_accessibility_node_id = iter->accessibility_node_id;
+        return true;
+      }
+    }
+
+    if (iter->browser_plugin_instance_id) {
+      WebContents* web_contents =
+          iter->parent_frame_host->delegate()->GetAsWebContents();
+      if (web_contents) {
+        BrowserPluginGuestManager* guest_manager =
+            web_contents->GetBrowserContext()->GetGuestManager();
+        WebContents* guest = guest_manager->GetGuestByInstanceID(
+            web_contents, iter->browser_plugin_instance_id);
+        if (guest->GetMainFrame() == child_frame_host) {
+          if (out_parent_frame_host)
+            *out_parent_frame_host = iter->parent_frame_host;
+          if (out_accessibility_node_id)
+            *out_accessibility_node_id = iter->accessibility_node_id;
+          return true;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
+}  // namespace content