Android webview fix gpu crashes after destroy

content/common/gpu/image_transport_surface_android.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/common/gpu/image_transport_surface.h"
 
 #include "base/logging.h"
 #include "content/common/gpu/gpu_surface_lookup.h"
 #include "content/common/gpu/texture_image_transport_surface.h"
 #include "ui/gl/gl_surface_egl.h"
 
 namespace content {
 
 // static
 scoped_refptr<gfx::GLSurface> ImageTransportSurface::CreateSurface(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub,
     const gfx::GLSurfaceHandle& handle) {
   scoped_refptr<gfx::GLSurface> surface;
   if (!handle.handle && handle.transport) {
     surface = new TextureImageTransportSurface(manager, stub, handle);
   } else if (handle.handle == gfx::kDummyPluginWindow && !handle.transport) {
     DCHECK(GpuSurfaceLookup::GetInstance());
     ANativeWindow* window = GpuSurfaceLookup::GetInstance()->GetNativeWidget(
         stub->surface_id());
-    DCHECK(window);
+    if (!window)
+      return NULL;  // May happen after AwContents.destroy

[no sievers, 2013/01/25 20:24:41]

Usually I'd think that this implies a bug (such as a race) in the code.
Does this happen because you quickly create and destroy a compositor (removing
the surface from the tracker) before we get a chance to create the context on
the gpu thread?

Wouldn't surface->Initialize() below fail if window was NULL?

The change is fine with me though. But you might want to add a LOG(ERROR) (maybe
also for the next return).

[boliu, 2013/01/25 21:27:02]

Yes, the process is create awcontents->load about:blank->destroy, I think the
whole thing is pretty fast.
So I'm seeing a null pointer exception in Initialize that's freaking me out
since I basically added DCHECKs for everything before where the crash is and
nothing appeared null. I'll post the stack crash in the bug if I can't figure it
out.
btw, LOG(ERROR) is equivalent to CHECK(false), did you really want to crash in
production too?

     surface = new gfx::NativeViewGLSurfaceEGL(false, window);
     if (!surface.get() || !surface->Initialize())
       return NULL;
 
     surface = new PassThroughImageTransportSurface(
         manager, stub, surface.get(), handle.transport);
   } else {
     NOTIMPLEMENTED();
     return NULL;
   }
 
   if (surface->Initialize())
     return surface;
   else {
     LOG(ERROR) << "Failed to initialize ImageTransportSurface";
     return NULL;
   }
 }
 
 }  // namespace content