Make gfx::Rect class operations consistently mutate the class they are called on.

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 <string>
 #include <utility>
 #include <vector>
 
 #include "ppapi/c/dev/ppb_console_dev.h"
 #include "ppapi/c/dev/ppb_cursor_control_dev.h"
@@ skipping 130 matching lines @@
         caret_pos_(std::string::npos),
         anchor_pos_(std::string::npos) {
     pp::FontDescription_Dev desc;
     desc.set_family(PP_FONTFAMILY_SANSSERIF);
     desc.set_size(font_size_);
     font_ = pp::Font_Dev(instance_, desc);
   }
 
   // Paint on the specified ImageData.
   void PaintOn(pp::ImageData* image, pp::Rect clip) {
-    clip = clip.Intersect(area_);
+    clip.Intersect(area_);
     FillRect(image, clip, kTextfieldBgColor);
 
     if (caret_pos_ != std::string::npos) {
       int offset = area_.x();
       // selection (for the case without composition text)
       if (composition_.empty() && HasSelection()) {
         int left_x = font_.MeasureSimpleText(
             utf8_text_.substr(0, SelectionLeft()));
         int right_x = font_.MeasureSimpleText(
             utf8_text_.substr(0, SelectionRight()));
@@ skipping 565 matching lines @@
   }
 };
 
 namespace pp {
 
 Module* CreateModule() {
   return new MyModule();
 }
 
 }  // namespace pp