aw: Fix race between first frame draw and view detach causing deadlock.

android_webview/browser/browser_view_renderer.h

 // Copyright (c) 2013 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.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_
 #define ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 186 matching lines @@
   float dip_scale_;
   float page_scale_factor_;
   float min_page_scale_factor_;
   float max_page_scale_factor_;
   bool on_new_picture_enable_;
   bool clear_view_;
 
   bool offscreen_pre_raster_;
 
   // Must do a synchronous draw first to ensure GL bindings are initialized.
-  // TODO(boliu): Wait on render thread and remove this.
+  // TODO(boliu): Wait on render thread and remove this. When the
+  // first synchronous draw requirement is removed,
+  // RenderThreadManager::DeleteHardwareRendererOnUI will need to
+  // change, because it will no longer be true that having received a
+  // frame means that GL bindings have been initialized.
   bool allow_async_draw_;
 
   gfx::Vector2d last_on_draw_scroll_offset_;
   gfx::Rect last_on_draw_global_visible_rect_;
 
   gfx::Size size_;
 
   gfx::SizeF scrollable_size_dip_;
 
   // Current scroll offset in CSS pixels.
@@ skipping 11 matching lines @@
   gfx::Vector2dF overscroll_rounding_error_;
 
   ParentCompositorDrawConstraints external_draw_constraints_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserViewRenderer);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_