Convert string16 to base::string16 in content.

content/renderer/android/content_detector.h

Index: content/renderer/android/content_detector.h
diff --git a/content/renderer/android/content_detector.h b/content/renderer/android/content_detector.h
index 85ee6688d6ff77cea306a592fc127cc38e1f6c45..28a153af8a05718907e4e7c05dc4c98ff2c154f2 100644
--- a/content/renderer/android/content_detector.h
+++ b/content/renderer/android/content_detector.h
@@ -44,8 +44,8 @@ class ContentDetector {
   // if the desired content is found. The start and end positions relative to
   // the input iterators are returned in start_pos and end_pos.
   // The end position is assumed to be non-inclusive.
-  virtual bool FindContent(const string16::const_iterator& begin,
-                           const string16::const_iterator& end,
+  virtual bool FindContent(const base::string16::const_iterator& begin,
+                           const base::string16::const_iterator& end,
                            size_t* start_pos,
                            size_t* end_pos,
                            std::string* content_text) = 0;