Change the SearchBox API from using the start/end margins of the location bar to using the start ma…

chrome/browser/ui/views/location_bar/location_bar_view.cc

Index: chrome/browser/ui/views/location_bar/location_bar_view.cc
diff --git a/chrome/browser/ui/views/location_bar/location_bar_view.cc b/chrome/browser/ui/views/location_bar/location_bar_view.cc
index 76f08525e6307eebd78f3774533db4a578360638..47ea574f398719d8e1ed3da69f01208679a8e7ae 100644
--- a/chrome/browser/ui/views/location_bar/location_bar_view.cc
+++ b/chrome/browser/ui/views/location_bar/location_bar_view.cc
@@ -1286,14 +1286,14 @@ bool LocationBarView::HasFocus() const {
 
 void LocationBarView::OnBoundsChanged(const gfx::Rect& previous_bounds) {
   if (browser_ && browser_->instant_controller() && parent()) {
-    // Pass the side margins of the location bar to the Instant Controller.
+    // Pass the start margin and width of the location bar to the Instant
+    // Controller.
     const gfx::Rect bounds = GetBoundsInScreen();
     const gfx::Rect parent_bounds = parent()->GetBoundsInScreen();
-    int start = bounds.x() - parent_bounds.x();
-    int end = parent_bounds.right() - bounds.right();
-    if (base::i18n::IsRTL())
-      std::swap(start, end);
-    browser_->instant_controller()->SetMarginSize(start, end);
+    const int margin = base::i18n::IsRTL() ?
+        parent_bounds.right() - bounds.right() : bounds.x() - parent_bounds.x();
+    const int width = bounds.width();
+    browser_->instant_controller()->SetStartMarginAndWidth(margin, width);
   }
 }