mac: Add support for asynchronous dictionary lookup

content/renderer/text_input_client_observer.cc

Index: content/renderer/text_input_client_observer.cc
diff --git a/content/renderer/text_input_client_observer.cc b/content/renderer/text_input_client_observer.cc
index 5ce95ff6093742ac828679019e22a9cbee097912..6eed645fb8d0b6204c939b9b923d862f670ae2f2 100644
--- a/content/renderer/text_input_client_observer.cc
+++ b/content/renderer/text_input_client_observer.cc
@@ -29,6 +29,8 @@ TextInputClientObserver::~TextInputClientObserver() {
 bool TextInputClientObserver::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(TextInputClientObserver, message)
+    IPC_MESSAGE_HANDLER(TextInputClientMsg_StringAtPoint,
+                        OnStringAtPoint)
     IPC_MESSAGE_HANDLER(TextInputClientMsg_CharacterIndexForPoint,
                         OnCharacterIndexForPoint)
     IPC_MESSAGE_HANDLER(TextInputClientMsg_FirstRectForCharacterRange,
@@ -43,6 +45,30 @@ blink::WebView* TextInputClientObserver::webview() {
   return render_view()->GetWebView();
 }
 
+void TextInputClientObserver::OnStringAtPoint(gfx::Point point) {

[Andre, 2014/02/18 21:35:02]

Given a point in view coordinates, find the closest word as attributed string
and also its containing rectangle. I'm trying it by adding the following code in
blink's WebFrameImpl.cpp, but it's probably completely wrong.
The intent is to show the dictionary definition popup for a word when
three-finger tapping, but without doing synchronous IPC to the renderer.
With this code it kind of works on a simple .txt file, other than the rect being
a little too low vertically. But it doesn't work on a simple page like
chromium.org for example.
Eric, I would appreciate some pointers on how to do this properly, thanks!

WebRange WebFrameImpl::rangeForWordAtPoint(const WebPoint& webPoint) const
{
    IntPoint point = frame()->view()->windowToContents(webPoint);
    HitTestResult result = frame()->eventHandler().hitTestResultAtPoint(point,
HitTestRequest::ReadOnly | HitTestRequest::Active |
HitTestRequest::ConfusingAndOftenMisusedDisallowShadowContent);
    RefPtr<Range> range =
frame()->rangeForPoint(result.roundedPointInInnerNodeFrame());
    VisibleSelection selection = VisibleSelection(range.get());
    selection.expandUsingGranularity(WordGranularity);
    return selection.toNormalizedRange();
}

+#if defined(OS_MACOSX)
+  blink::WebFrame* frame = webview()->focusedFrame();
+  NSAttributedString* string = nil;
+  gfx::Rect rect;
+  if (frame) {
+    blink::WebRange range = frame->rangeForWordAtPoint(point);
+    int length = range.endOffset() - range.startOffset();
+    string = blink::WebSubstringUtil::attributedSubstringInRange(
+        frame, range.startOffset(), length);
+
+    blink::WebRect web_rect;
+    frame->firstRectForCharacterRange(range.startOffset(), length, web_rect);
+    rect = web_rect;
+  }
+  scoped_ptr<const mac::AttributedStringCoder::EncodedString> encoded(
+      mac::AttributedStringCoder::Encode(string));
+  Send(new TextInputClientReplyMsg_GotStringAtPoint(routing_id(),
+      *encoded.get(), rect));
+#else
+  NOTIMPLEMENTED();
+#endif
+}
+
 void TextInputClientObserver::OnCharacterIndexForPoint(gfx::Point point) {
   blink::WebPoint web_point(point);
   size_t index = webview()->focusedFrame()->characterIndexForPoint(web_point);