Mac: move content::RenderWidgetResizeHelper to ui::WindowResizeHelperMac (acelerated_widget_mac)

content/browser/browser_main_loop.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 "content/browser/browser_main_loop.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 90 matching lines @@
 #endif
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 #include "base/memory/memory_pressure_monitor_mac.h"
 #include "content/browser/bootstrap_sandbox_mac.h"
 #include "content/browser/browser_io_surface_manager_mac.h"
 #include "content/browser/cocoa/system_hotkey_helper_mac.h"
 #include "content/browser/compositor/browser_compositor_view_mac.h"
 #include "content/browser/in_process_io_surface_manager_mac.h"
 #include "content/browser/theme_helper_mac.h"
+#include "ui/accelerated_widget_mac/window_resize_helper_mac.h"
 #endif
 
 #if defined(USE_OZONE)
 #include "ui/ozone/public/client_native_pixmap_factory.h"
 #include "ui/ozone/public/ozone_platform.h"
 #endif
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <commctrl.h>
@@ skipping 573 matching lines @@
 
 #if defined(OS_MACOSX)
   {
     // Initialize AVFoundation if supported, for audio and video.
     TRACE_EVENT0("startup",
                  "BrowserMainLoop::CreateThreads:InitializeAVFoundation");
     AVFoundationGlue::InitializeAVFoundation();
   }
 #endif
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // The WindowResizeHelper synchronizes IO thread tasks with the UI thread.

[jam, 2015/09/17 23:25:16]

can you describe this some more? are we making the UI thread wait on the IO, or
vice versa?

[tapted, 2015/09/18 00:36:55]

Updated the comment, now says

  // The WindowResizeHelper allows the UI thread to wait on specific renderer
  // and GPU messages from the IO thread. Initializing it before the IO thread
  // starts ensures the affected IO thread messages always have somewhere to go.

There's also a lot of specific details in the WindowResizeHelper class comment
in ui/accelerated_widget_mac/window_resize_helper_mac.h

+  ui::WindowResizeHelperMac::Get()->Init(base::ThreadTaskRunnerHandle::Get());
+#endif
+
   // 1) Need to initialize in-process GpuDataManager before creating threads.
   // It's unsafe to append the gpu command line switches to the global
   // CommandLine::ForCurrentProcess object after threads are created.
   // 2) Must be after parts_->PreCreateThreads to pick up chrome://flags.
   GpuDataManagerImpl::GetInstance()->Initialize();
 
 #if !defined(OS_IOS) && (!defined(GOOGLE_CHROME_BUILD) || defined(OS_ANDROID))
   // Single-process is an unsupported and not fully tested mode, so
   // don't enable it for official Chrome builds (except on Android).
   if (parsed_command_line_.HasSwitch(switches::kSingleProcess))
@@ skipping 669 matching lines @@
   DCHECK(is_tracing_startup_for_duration_);
 
   is_tracing_startup_for_duration_ = false;
   TracingController::GetInstance()->DisableRecording(
       TracingController::CreateFileSink(
           startup_trace_file_,
           base::Bind(OnStoppedStartupTracing, startup_trace_file_)));
 }
 
 }  // namespace content