Add a dummy implementation of a new WebWidget::confirmComposition() method.

chrome/renderer/render_widget_fullscreen_pepper.cc

Index: chrome/renderer/render_widget_fullscreen_pepper.cc
diff --git a/chrome/renderer/render_widget_fullscreen_pepper.cc b/chrome/renderer/render_widget_fullscreen_pepper.cc
index 42b7a931ddf01f385f3277be5d266829a9bb997e..539da366e7e82136e76bfda2441e34161b2fee89 100644
--- a/chrome/renderer/render_widget_fullscreen_pepper.cc
+++ b/chrome/renderer/render_widget_fullscreen_pepper.cc
@@ -99,6 +99,11 @@ class PepperWidget : public WebWidget {
     return false;
   }
 
+  virtual bool confirmComposition(const WebString& text) {
+    NOTIMPLEMENTED();
+    return false;
+  }
+
   virtual WebTextInputType textInputType() {
     NOTIMPLEMENTED();
     return WebKit::WebTextInputTypeNone;