Fix output surface Memory Dump Provider unregistration.

cc/output/output_surface.cc

 // 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.
 
 #include "cc/output/output_surface.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 172 matching lines @@
     bool resourceless_software_draw) {
   client_->SetExternalDrawConstraints(transform,
                                       viewport,
                                       clip,
                                       viewport_rect_for_tile_priority,
                                       transform_for_tile_priority,
                                       resourceless_software_draw);
 }
 
 OutputSurface::~OutputSurface() {
-  // Unregister any dump provider. Safe to call (no-op) if we have not yet
-  // registered.
-  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
-      this);
-
   if (client_)
     DetachFromClientInternal();
 }
 
 bool OutputSurface::HasExternalStencilTest() const {
   return external_stencil_test_enabled_;
 }
 
 bool OutputSurface::BindToClient(OutputSurfaceClient* client) {
   DCHECK(client_thread_checker_.CalledOnValidThread());
@@ skipping 11 matching lines @@
           base::Bind(&OutputSurface::SetMemoryPolicy, base::Unretained(this)));
     }
   }
 
   if (!success)
     client_ = NULL;
 
   // In certain cases, ThreadTaskRunnerHandle isn't set (Android Webview).
   // Don't register a dump provider in these cases.
   // TODO(ericrk): Get this working in Android Webview. crbug.com/517156
-  if (base::ThreadTaskRunnerHandle::IsSet()) {
+  if (client_ && base::ThreadTaskRunnerHandle::IsSet()) {
     // Now that we are on the context thread, register a dump provider with this
     // thread's task runner. This will overwrite any previous dump provider
     // registered.
     base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
         this, base::ThreadTaskRunnerHandle::Get());
   }
 
   return success;
 }
 
@@ skipping 104 matching lines @@
       gr_context->dumpMemoryStatistics(&trace_memory_dump);
     }
   }
 
   return true;
 }
 
 void OutputSurface::DetachFromClientInternal() {
   DCHECK(client_thread_checker_.CalledOnValidThread());
   DCHECK(client_);
+
+  // Unregister any dump provider. Safe to call (no-op) if we have not yet
+  // registered.
+  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
+      this);
+
   if (context_provider_.get()) {
     context_provider_->SetLostContextCallback(
         ContextProvider::LostContextCallback());
     context_provider_->SetMemoryPolicyChangedCallback(
         ContextProvider::MemoryPolicyChangedCallback());
   }
   context_provider_ = nullptr;
   client_ = nullptr;
   weak_ptr_factory_.InvalidateWeakPtrs();
 }
 
 }  // namespace cc