Enable size_t to int truncation warnings in PPAPI

ppapi/examples/ime/ime.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 <algorithm>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "ppapi/c/dev/ppb_cursor_control_dev.h"
@@ skipping 94 matching lines @@
   // Implement TextFieldStatusHandler.
   virtual void FocusIn(const pp::Rect& caret) {
     textinput_control_.SetTextInputType(PP_TEXTINPUT_TYPE_TEXT);
     textinput_control_.UpdateCaretPosition(caret);
   }
   virtual void FocusOut() {
     textinput_control_.CancelCompositionText();
     textinput_control_.SetTextInputType(PP_TEXTINPUT_TYPE_NONE);
   }
   virtual void UpdateSelection(const std::string& text) {
-    textinput_control_.UpdateSurroundingText(text, 0, text.size());
+    textinput_control_.UpdateSurroundingText(
+        text, 0, static_cast<uint32_t>(text.size()));
   }
 
  private:
   pp::TextInputController textinput_control_;
 };
 
 // Hand-made text field for demonstrating text input API.
 class MyTextField {
  public:
   MyTextField(pp::Instance* instance, TextFieldStatusHandler* handler,
@@ skipping 598 matching lines @@
   }
 };
 
 namespace pp {
 
 Module* CreateModule() {
   return new MyModule();
 }
 
 }  // namespace pp