Add non-member non-mutating methods for common gfx::Rect operations.

chrome/browser/instant/instant_controller.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 "chrome/browser/instant/instant_controller.h"
 
 #include "base/command_line.h"
 #include "base/i18n/case_conversion.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
@@ skipping 726 matching lines @@
   model_.SetDisplayState(InstantModel::QUERY_RESULTS, height, units);
 }
 
 void InstantController::SendBoundsToPage() {
   if (last_omnibox_bounds_ == omnibox_bounds_ || IsOutOfDate() ||
       !GetPreviewContents() || loader_->IsPointerDownFromActivate())
     return;
 
   last_omnibox_bounds_ = omnibox_bounds_;
   gfx::Rect preview_bounds = browser_->GetInstantBounds();
-  gfx::Rect intersection = omnibox_bounds_;
-  intersection.Intersect(preview_bounds);
+  gfx::Rect intersection = gfx::IntersectRects(omnibox_bounds_, preview_bounds);
 
   // Translate into window coordinates.
   if (!intersection.IsEmpty()) {
     intersection.Offset(-preview_bounds.origin().x(),
                         -preview_bounds.origin().y());
   }
 
   // In the current Chrome UI, these must always be true so they sanity check
   // the above operations. In a future UI, these may be removed or adjusted.
   // There is no point in sanity-checking |intersection.y()| because the omnibox
@@ skipping 56 matching lines @@
       iter->second > kMaxInstantSupportFailures)
     return false;
 
   return true;
 }
 
 bool InstantController::IsOutOfDate() const {
   return !last_active_tab_ ||
          last_active_tab_ != browser_->GetActiveTabContents();
 }