Avoid sync IPCs for firstRectForCharacterRange/attributedSubstringForProposedRange.

content/browser/renderer_host/render_widget_host_view_mac.h

Index: content/browser/renderer_host/render_widget_host_view_mac.h
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.h b/content/browser/renderer_host/render_widget_host_view_mac.h
index f01906e36fa23dbdc794df756c6017db42245ffd..ef06ca14901213c3b8d90a01bf8d8a566bbe1537 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -361,6 +361,8 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   void PluginImeCompositionCompleted(const base::string16& text, int plugin_id);
 
   const std::string& selected_text() const { return selected_text_; }
+  const gfx::Range& composition_range() const { return composition_range_; }
+  const gfx::Range& selection_range() const { return selection_range_; }
 
   // Returns true and stores first rectangle for character range if the
   // requested |range| is already cached, otherwise returns false.
@@ -585,6 +587,9 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   // The current caret bounds.
   gfx::Rect caret_rect_;
 
+  // The current first selection bounds.
+  gfx::Rect first_selection_rect_;
+
   // Factory used to safely scope delayed calls to ShutdownHost().
   base::WeakPtrFactory<RenderWidgetHostViewMac> weak_factory_;