Replace string16 with base::string16 in src/webkit

webkit/plugins/ppapi/mock_plugin_delegate.cc

Index: webkit/plugins/ppapi/mock_plugin_delegate.cc
diff --git a/webkit/plugins/ppapi/mock_plugin_delegate.cc b/webkit/plugins/ppapi/mock_plugin_delegate.cc
index 137c0617b1310be725c89a4a0bf6084a4679edf6..07c963e61f6004db1ed88a77269e4d78b9017ca3 100644
--- a/webkit/plugins/ppapi/mock_plugin_delegate.cc
+++ b/webkit/plugins/ppapi/mock_plugin_delegate.cc
@@ -40,13 +40,14 @@ void MockPluginDelegate::PluginSelectionChanged(PluginInstance* instance) {
 }
 
 void MockPluginDelegate::SimulateImeSetComposition(
-    const string16& text,
+    const base::string16& text,
     const std::vector<WebKit::WebCompositionUnderline>& underlines,
     int selection_start,
     int selection_end) {
 }
 
-void MockPluginDelegate::SimulateImeConfirmComposition(const string16& text) {
+void MockPluginDelegate::SimulateImeConfirmComposition(
+    const base::string16& text) {
 }
 
 void MockPluginDelegate::PluginCrashed(PluginInstance* instance) {