[TTS] Extract tapped text before showing UI.

chrome/browser/android/contextualsearch/contextual_search_delegate.cc

 // Copyright 2015 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 "chrome/browser/android/contextualsearch/contextual_search_delegate.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/base64.h"
@@ skipping 292 matching lines @@
   SaveSurroundingText(surrounding_text, start_offset, end_offset);
   if (context_->CanResolve())
     SendSurroundingText(kSurroundingSizeForUI);
 }
 
 void ContextualSearchDelegate::SaveSurroundingText(
     const base::string16& surrounding_text,
     int start_offset,
     int end_offset) {
   DCHECK(context_ != nullptr);
-  // Sometimes the surroundings are 0, 0, '', so fall back on the selection.
+  // Sometimes the surroundings are 0, 0, '', so exit in that case.
   // See crbug.com/393100.
-  bool use_selection = false;
-  if (start_offset == 0 && end_offset == 0 && surrounding_text.length() == 0) {
-    use_selection = true;
-    end_offset = context_->GetOriginalSelectedText().length();
-  }
-  const base::string16& surrounding_text_or_selection(
-      use_selection ? base::UTF8ToUTF16(context_->GetOriginalSelectedText())
-                    : surrounding_text);
+  if (start_offset == 0 && end_offset == 0 && surrounding_text.length() == 0)
+    return;
 
   // Pin the start and end offsets to ensure they point within the string.
-  int surrounding_length = surrounding_text_or_selection.length();
+  int surrounding_length = surrounding_text.length();
   start_offset = std::min(surrounding_length, std::max(0, start_offset));
   end_offset = std::min(surrounding_length, std::max(0, end_offset));
 
   context_->SetSelectionSurroundings(start_offset, end_offset,
-                                     surrounding_text_or_selection);
+                                     surrounding_text);
 
   // Call the Icing callback with a shortened copy of the surroundings.
   int icing_surrounding_size = field_trial_->GetIcingSurroundingSize();
-  size_t selection_start = start_offset;
-  size_t selection_end = end_offset;
-  if (icing_surrounding_size >= 0 && selection_start <= selection_end) {
+  if (icing_surrounding_size >= 0 && start_offset <= end_offset) {
+    size_t selection_start = start_offset;
+    size_t selection_end = end_offset;
     int icing_padding_each_side = icing_surrounding_size / 2;
-    base::string16 icing_surrounding_text = SurroundingTextForIcing(
-        surrounding_text_or_selection, icing_padding_each_side,
-        &selection_start, &selection_end);
+    base::string16 icing_surrounding_text =
+        SurroundingTextForIcing(surrounding_text, icing_padding_each_side,
+                                &selection_start, &selection_end);
     if (selection_start <= selection_end)
       icing_callback_.Run(context_->GetBasePageEncoding(),
                           icing_surrounding_text, selection_start,
                           selection_end);
   }
 }
 
 void ContextualSearchDelegate::SendSurroundingText(int max_surrounding_chars) {
   DCHECK(context_ != nullptr);
   const base::string16& surrounding = context_->GetSurroundingText();
@@ skipping 232 matching lines @@
     end_offset -= trim;
   }
   if (result_text.length() > end_offset + padding_each_side_pinned) {
     // Trim the end.
     result_text = result_text.substr(0, end_offset + padding_each_side_pinned);
   }
   *start = start_offset;
   *end = end_offset;
   return result_text;
 }