Handling firstRectForCharacterRange when range argument has invalid range (Mac)

content/renderer/text_input_client_observer.cc

 // Copyright (c) 2012 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/renderer/text_input_client_observer.h"
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "build/build_config.h"
 #include "content/common/text_input_client_messages.h"
 #include "content/renderer/pepper/pepper_plugin_instance_impl.h"
 #include "content/renderer/render_frame_impl.h"
 #include "content/renderer/render_view_impl.h"
 #include "content/renderer/render_widget.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/features/features.h"
 #include "third_party/WebKit/public/platform/WebPoint.h"
 #include "third_party/WebKit/public/platform/WebRect.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "third_party/WebKit/public/web/mac/WebSubstringUtil.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace content {
 
+namespace {
+uint32_t GetCurrentCursorPositionInFrame(blink::WebLocalFrame* localFrame) {
+  blink::WebRange range = localFrame->selectionRange();
+  return range.isNull() ? 0U : static_cast<uint32_t>(range.startOffset());
+}
+}
+
 TextInputClientObserver::TextInputClientObserver(RenderWidget* render_widget)
     : render_widget_(render_widget) {}
 
 TextInputClientObserver::~TextInputClientObserver() {
 }
 
 bool TextInputClientObserver::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(TextInputClientObserver, message)
     IPC_MESSAGE_HANDLER(TextInputClientMsg_StringAtPoint,
@@ skipping 87 matching lines @@
   if (focused_plugin) {
     rect = focused_plugin->GetCaretBounds();
   } else
 #endif
   {
     blink::WebLocalFrame* frame = GetFocusedFrame();
     // TODO(yabinh): Null check should not be necessary.
     // See crbug.com/304341
     if (frame) {
       blink::WebRect web_rect;
-      frame->firstRectForCharacterRange(range.start(), range.length(),
-                                        web_rect);
+      // When request range is invalid we will try to obtain it from current
+      // frame selection. The fallback value will be 0.
+      uint32_t start = range.IsValid() ? range.start()
+                                       : GetCurrentCursorPositionInFrame(frame);
+      frame->firstRectForCharacterRange(start, range.length(), web_rect);
       rect = web_rect;
     }
   }
   Send(new TextInputClientReplyMsg_GotFirstRectForRange(
       render_widget_->routing_id(), rect));
 }
 
 void TextInputClientObserver::OnStringForRange(gfx::Range range) {
 #if defined(OS_MACOSX)
   blink::WebPoint baselinePoint;
   NSAttributedString* string = nil;
   blink::WebLocalFrame* frame = GetFocusedFrame();
   // TODO(yabinh): Null check should not be necessary.
   // See crbug.com/304341
   if (frame) {
     string = blink::WebSubstringUtil::attributedSubstringInRange(
         frame, range.start(), range.length(), &baselinePoint);
   }
   std::unique_ptr<const mac::AttributedStringCoder::EncodedString> encoded(
       mac::AttributedStringCoder::Encode(string));
   Send(new TextInputClientReplyMsg_GotStringForRange(
       render_widget_->routing_id(), *encoded.get(), baselinePoint));
 #else
   NOTIMPLEMENTED();
 #endif
 }
 
 }  // namespace content