Fix case handling in Instant suggestions.

chrome/browser/instant/instant_controller.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 "chrome/browser/instant/instant_controller.h"
 
 #include "base/command_line.h"
 #include "base/i18n/case_conversion.h"
 #include "base/metrics/histogram.h"
 #include "base/time.h"
@@ skipping 491 matching lines @@
     // suggestion (so that we don't inadvertently cause the preview to change
     // what it's showing, as the user arrows up/down through the page-provided
     // suggestions). So, update these state variables here.
     last_full_text_ = suggestion.text;
     last_user_text_.clear();
     last_verbatim_ = true;
     last_suggestion_ = InstantSuggestion();
     last_match_was_search_ = suggestion.type == INSTANT_SUGGESTION_SEARCH;
     delegate_->SetSuggestedText(suggestion.text, suggestion.behavior);
   } else {
-    string16 suggestion_lower = base::i18n::ToLower(suggestion.text);
-    string16 user_text_lower = base::i18n::ToLower(last_user_text_);
-    if (user_text_lower.size() >= suggestion_lower.size() ||
-        suggestion_lower.compare(0, user_text_lower.size(), user_text_lower))
-      suggestion.text.clear();
-    else
+    // Match case-sensitively first, to preserve suggestion case if possible.
+    // If that fails, match case-insensitively. http://crbug.com/150728
+    if (last_user_text_.size() < suggestion.text.size() &&
+        !suggestion.text.compare(0, last_user_text_.size(), last_user_text_)) {
       suggestion.text.erase(0, last_user_text_.size());
+    } else {
+      string16 suggestion_lower = base::i18n::ToLower(suggestion.text);
+      string16 user_text_lower = base::i18n::ToLower(last_user_text_);
+      if (user_text_lower.size() < suggestion_lower.size() &&
+          !suggestion_lower.compare(0, user_text_lower.size(),
+                                    user_text_lower)) {
+        suggestion.text.assign(suggestion_lower, user_text_lower.size(),
+            suggestion_lower.size() - user_text_lower.size());
+      } else {
+        suggestion.text.clear();
+      }
+    }
 
     last_suggestion_ = suggestion;
     if (!last_verbatim_)
       delegate_->SetSuggestedText(suggestion.text, suggestion.behavior);
   }
 
   if (mode_ != SUGGEST)
     Show(100, INSTANT_SIZE_PERCENT);
 }
 
@@ skipping 259 matching lines @@
       DCHECK(url_obj.is_valid());
       *instant_url = url_obj.spec();
     }
   }
 }
 
 bool InstantController::IsOutOfDate() const {
   return !last_active_tab_ ||
          last_active_tab_ != delegate_->GetActiveTabContents();
 }