Implement accessibility support for CSS-transformed iframes.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 188d17aa0ca0c565ff027ece42dc20d770271c51..8d3a6c38359eae99c0b023b93963f87a1b4ce145 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -76,6 +76,7 @@
 #include "content/public/common/url_utils.h"
 #include "ui/accessibility/ax_tree.h"
 #include "ui/accessibility/ax_tree_update.h"
+#include "ui/gfx/geometry/quad_f.h"
 #include "url/gurl.h"
 
 #if defined(OS_ANDROID)
@@ -650,6 +651,21 @@ gfx::Point RenderFrameHostImpl::AccessibilityOriginInScreen(
   return gfx::Point();
 }
 
+void RenderFrameHostImpl::AccessibilityTransformToRootCoordSpace(
+    gfx::Rect* bounds) {
+  RenderWidgetHostViewBase* view =
+      static_cast<RenderWidgetHostViewBase*>(GetView());
+  gfx::Point p1 = view->TransformPointToRootCoordSpace(bounds->origin());
+  gfx::Point p2 = view->TransformPointToRootCoordSpace(bounds->top_right());
+  gfx::Point p3 = view->TransformPointToRootCoordSpace(bounds->bottom_right());
+  gfx::Point p4 = view->TransformPointToRootCoordSpace(bounds->bottom_left());
+  gfx::QuadF transformed_quad = gfx::QuadF(
+      gfx::PointF(p1), gfx::PointF(p2), gfx::PointF(p3), gfx::PointF(p4));
+  gfx::RectF new_bounds = transformed_quad.BoundingBox();
+  *bounds = gfx::Rect(new_bounds.x(), new_bounds.y(),
+                      new_bounds.width(), new_bounds.height());
+}
+
 void RenderFrameHostImpl::AccessibilityHitTest(const gfx::Point& point) {
   Send(new AccessibilityMsg_HitTest(routing_id_, point));
 }