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

content/browser/renderer_host/render_widget_host_view_aura.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 "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 417 matching lines @@
   gfx::Rect view_bounds = window_->GetBoundsInRootWindow();
   std::vector<webkit::npapi::WebPluginGeometry> moves = plugin_window_moves;
 
   gfx::Rect view_port(scroll_offset.x(), scroll_offset.y(), view_bounds.width(),
                       view_bounds.height());
 
   for (size_t i = 0; i < moves.size(); ++i) {
     gfx::Rect clip = moves[i].clip_rect;
     clip.Offset(moves[i].window_rect.origin());
     clip.Offset(scroll_offset);
-    clip = clip.Intersect(view_port);
+    clip.Intersect(view_port);
     clip.Offset(-moves[i].window_rect.x(), -moves[i].window_rect.y());
     clip.Offset(-scroll_offset.x(), -scroll_offset.y());
     moves[i].clip_rect = clip;
 
     moves[i].window_rect.Offset(view_bounds.origin());
   }
   MovePluginWindowsHelper(parent, moves);
 
   // Make sure each plugin window (or its wrapper if it exists) has a pointer to
   // |this|.
@@ skipping 418 matching lines @@
     gfx::Rect rect_to_paint = ConvertRectToDIP(this, gfx::Rect(
         params_in_pixel.x,
         surface_size_in_pixel.height() - params_in_pixel.y -
             params_in_pixel.height,
         params_in_pixel.width,
         params_in_pixel.height));
 
     // Damage may not have been DIP aligned, so inflate damage to compensate
     // for any round-off error.
     rect_to_paint.Inset(-1, -1);
-    rect_to_paint = rect_to_paint.Intersect(window_->bounds());
+    rect_to_paint.Intersect(window_->bounds());
 
     window_->SchedulePaintInRect(rect_to_paint);
 
     if (!resize_locks_.empty()) {
       // If we are waiting for the resize, fast-track the ACK.
       if (compositor->IsThreaded()) {
         // We need the compositor thread to pick up the active buffer before
         // ACKing.
         on_compositing_did_commit_callbacks_.push_back(
             base::Bind(&RenderWidgetHostViewAura::InsertSyncPointAndACK,
@@ skipping 986 matching lines @@
     RenderWidgetHost* widget) {
   return new RenderWidgetHostViewAura(widget);
 }
 
 // static
 void RenderWidgetHostViewPort::GetDefaultScreenInfo(WebScreenInfo* results) {
   GetScreenInfoForWindow(results, NULL);
 }
 
 }  // namespace content