[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

components/autofill/content/renderer/form_autofill_util.cc

 // Copyright 2013 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 "components/autofill/content/renderer/form_autofill_util.h"
 
 #include <map>
 #include <set>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/autofill/core/common/autofill_data_validation.h"
 #include "components/autofill/core/common/autofill_switches.h"
+#include "components/autofill/core/common/autofill_util.h"
 #include "components/autofill/core/common/form_data.h"
 #include "components/autofill/core/common/form_field_data.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebElementCollection.h"
 #include "third_party/WebKit/public/web/WebFormControlElement.h"
 #include "third_party/WebKit/public/web/WebFormElement.h"
 #include "third_party/WebKit/public/web/WebInputElement.h"
@@ skipping 847 matching lines @@
       data.value.substr(0, input_element->maxLength()));
     input_element->setAutofilled(true);
   } else if (IsTextAreaElement(*field) || IsSelectElement(*field)) {
     field->setSuggestedValue(data.value);
     field->setAutofilled(true);
   }
 
   if (is_initiating_node &&
       (IsTextInput(input_element) || IsTextAreaElement(*field))) {
     // Select the part of the text that the user didn't type.
-    int start = field->value().length();
-    int end = field->suggestedValue().length();
-    field->setSelectionRange(start, end);
+    if (IsFeatureSubstringMatchEnabled()) {
+      size_t start = 0;
+      size_t end = 0;
+      if (base::string16::npos !=
+          autofill::ComputeRange(field->suggestedValue(), field->value(),

[Evan Stade, 2015/03/31 21:41:52]

can you use StartsAt directly

[Pritam Nikam, 2015/04/01 09:10:37]

StartsAt() is not equipped handle all complected cases.

for eg. 
1. field_suggestion = L"ba.a.ab"  and field_contents = L"a.a"
   
   After executing ComputeRange() ->
   offset = 3, start = 6 & end = 7.

2. field_suggestion = L"texample@example.com" and field_contents = L"example"

   After executing ComputeRange() ->
   offset = 9, start = 16 & end = 20.

IMO StartsAt() shall handle only basic case i.e. to return the first occurrence
offset of search string. And ComputeRange() shall use it to get actual data
(i.e. selection start and end indexes) that we are interested in.

I've modified ComputeRange() to meet these these cases.

+                                 &start, &end)) {
+        field->setSelectionRange(start, end);
+      }
+    } else {
+      field->setSelectionRange(field->value().length(),
+                               field->suggestedValue().length());
+    }
   }
 }
 
 // Recursively checks whether |node| or any of its children have a non-empty
 // bounding box. The recursion depth is bounded by |depth|.
 bool IsWebNodeVisibleImpl(const blink::WebNode& node, const int depth) {
   if (depth < 0)
     return false;
   if (node.hasNonEmptyBoundingBox())
     return true;
@@ skipping 642 matching lines @@
 
 gfx::RectF GetScaledBoundingBox(float scale, WebElement* element) {
   gfx::Rect bounding_box(element->boundsInViewportSpace());
   return gfx::RectF(bounding_box.x() * scale,
                     bounding_box.y() * scale,
                     bounding_box.width() * scale,
                     bounding_box.height() * scale);
 }
 
 }  // namespace autofill