gpu: Reduce direct use of BrowserGpuMemoryBufferManager

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 6e9ddad3fdc8f91535b7cfdc2640f91fe7321525..479a7fd82a4e1f489c44f8177db07e8c4f73c177 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -63,7 +63,6 @@
 #include "content/browser/download/download_resource_handler.h"
 #include "content/browser/download/save_file_manager.h"
 #include "content/browser/gpu/browser_gpu_channel_host_factory.h"
-#include "content/browser/gpu/browser_gpu_memory_buffer_manager.h"
 #include "content/browser/gpu/compositor_util.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
 #include "content/browser/gpu/gpu_process_host.h"
@@ -1229,10 +1228,6 @@ void BrowserMainLoop::ShutdownThreadsAndCleanUp() {
   device_monitor_mac_.reset();
 #endif
 
-  if (BrowserGpuChannelHostFactory::instance()) {
-    BrowserGpuChannelHostFactory::instance()->CloseChannel();

[piman, 2017/07/07 03:57:10]

I'm surprised we don't need this. The GpuChannelHost needs the IO thread to post
tasks, otherwise I don't think it can clean up correctly...

[sadrul, 2017/07/08 03:19:33]

What kind of failures do you think we might have? The task-runners for the
threads are retained when the threads are shut down, so code that attempts to
post-task on the IO thread will not crash. But those tasks will never run
either, of course. I am not sure what kind of clean up works happen in those
tasks though. I notice the ipc support is torn down before the IO thread is
destroyed (see below in line ~1238), so if any of the posted tasks did any IPC,
they won't be processed anyway. Are there other issues I should watch for?
(memory leaks, perhaps?)

(fwiw, the trybots have been fairly OK with the change)

-  }
-
   // Shutdown the Service Manager and IPC.
   service_manager_context_.reset();
   mojo_ipc_support_.reset();
@@ -1475,12 +1470,6 @@ int BrowserMainLoop::BrowserThreadsStarted() {
 #endif  // defined(USE_AURA)
 #endif  // defined(OS_ANDROID)
 
-  // Enable the GpuMemoryBuffer dump provider with IO thread affinity. Note that
-  // unregistration happens on the IO thread (See
-  // BrowserProcessSubThread::IOThreadPreCleanUp).
-  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
-      BrowserGpuMemoryBufferManager::current(), "BrowserGpuMemoryBufferManager",
-      io_thread_->task_runner());
 #if defined(OS_ANDROID)
   base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
       tracing::GraphicsMemoryDumpProvider::GetInstance(), "AndroidGraphics",