Manky attempt with TextInputClient

ui/accessibility/platform/ax_platform_node_mac.mm

Index: ui/accessibility/platform/ax_platform_node_mac.mm
diff --git a/ui/accessibility/platform/ax_platform_node_mac.mm b/ui/accessibility/platform/ax_platform_node_mac.mm
index 62936942cb6eb03e7bf5a5d08d545c1d183d1ac8..ed2135ec33b1edc74ba53f980c864d7b646e5dde 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -15,7 +15,10 @@
 #include "ui/accessibility/platform/ax_platform_node.h"
 #include "ui/accessibility/platform/ax_platform_node_delegate.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/text/text_properties.h"
+#include "ui/gfx/geometry/rect.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
+#include "ui/gfx/range/range.h"
 #include "ui/strings/grit/ui_strings.h"
 
 namespace {
@@ -701,9 +704,19 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
 
 - (id)AXBoundsForRange:(id)parameter {
   DCHECK([parameter isKindOfClass:[NSValue class]]);
-  // TODO(tapted): Provide an accessor on AXPlatformNodeDelegate to obtain this
-  // from ui::TextInputClient::GetCompositionCharacterBounds().
-  NOTIMPLEMENTED();
+  if (ui::TextInputClient* text = node_->GetDelegate()->GetTextInputClient()) {
+    gfx::Range actualRange;
+    gfx::Rect rect = ui::GetFirstRectForTextInputRange(
+        text, gfx::Range([parameter rangeValue]), &actualRange);
+    // GetFirstRectForTextInputRange() can "fail", in which case it returns
+    // the caret bounds. That might be weird.
+    rect.set_width(30);
+    DLOG(INFO) << text << " -> " << actualRange.ToString() << " -> "
+               << rect.ToString();
+    return [NSValue valueWithRect:gfx::ScreenRectToNSRect(rect)];
+  } else {
+    DLOG(INFO) << "it null";
+  }
   return nil;
 }