Remove RWHV::SetBounds() from the public API, and make comments clearer.

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 3395188313c87beea099e7e6bccffd511549acce..af1481600b58e32e580fe2fd08939c5c02eef4c1 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -257,7 +257,6 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   void InitAsChild(gfx::NativeView parent_view) override;
   RenderWidgetHost* GetRenderWidgetHost() const override;
   void SetSize(const gfx::Size& size) override;
-  void SetBounds(const gfx::Rect& rect) override;
   gfx::Vector2dF GetLastScrollOffset() const override;
   gfx::NativeView GetNativeView() const override;
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
@@ -283,6 +282,7 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   void InitAsPopup(RenderWidgetHostView* parent_host_view,
                    const gfx::Rect& pos) override;
   void InitAsFullscreen(RenderWidgetHostView* reference_host_view) override;
+  void RequestTopLevelBoundsInScreen(const gfx::Rect& rect) override;
   void Focus() override;
   void UpdateCursor(const WebCursor& cursor) override;
   void SetIsLoading(bool is_loading) override;